diff --git a/ios/include/v8/libplatform/DEPS b/ios/include/v8/libplatform/DEPS
deleted file mode 100644
index d8bcf998..00000000
--- a/ios/include/v8/libplatform/DEPS
+++ /dev/null
@@ -1,9 +0,0 @@
-include_rules = [
-  "+libplatform/libplatform-export.h",
-]
-
-specific_include_rules = {
-  "libplatform\.h": [
-    "+libplatform/v8-tracing.h",
-  ],
-}
diff --git a/ios/include/v8/libplatform/v8-tracing.h b/ios/include/v8/libplatform/v8-tracing.h
index 0eb7f4be..bc249cb9 100644
--- a/ios/include/v8/libplatform/v8-tracing.h
+++ b/ios/include/v8/libplatform/v8-tracing.h
@@ -23,8 +23,6 @@ class Mutex;
 namespace platform {
 namespace tracing {
 
-class PerfettoTracingController;
-
 const int kTraceMaxNumArgs = 2;
 
 class V8_PLATFORM_EXPORT TraceObject {
@@ -240,11 +238,6 @@ class V8_PLATFORM_EXPORT TracingController
   TracingController();
   ~TracingController() override;
   void Initialize(TraceBuffer* trace_buffer);
-#ifdef V8_USE_PERFETTO
-  // Must be called before StartTracing() if V8_USE_PERFETTO is true. Provides
-  // the output stream for the JSON trace data.
-  void InitializeForPerfetto(std::ostream* output_stream);
-#endif
 
   // v8::TracingController implementation.
   const uint8_t* GetCategoryGroupEnabled(const char* category_group) override;
@@ -287,11 +280,6 @@ class V8_PLATFORM_EXPORT TracingController
   std::unique_ptr<base::Mutex> mutex_;
   std::unordered_set<v8::TracingController::TraceStateObserver*> observers_;
   std::atomic_bool recording_{false};
-#ifdef V8_USE_PERFETTO
-  std::atomic_bool perfetto_recording_{false};
-  std::unique_ptr<PerfettoTracingController> perfetto_tracing_controller_;
-  std::ostream* output_stream_ = nullptr;
-#endif
 
   // Disallow copy and assign
   TracingController(const TracingController&) = delete;
diff --git a/ios/include/v8/v8-inspector.h b/ios/include/v8/v8-inspector.h
index b96a6e29..70201358 100644
--- a/ios/include/v8/v8-inspector.h
+++ b/ios/include/v8/v8-inspector.h
@@ -87,6 +87,7 @@ class V8_EXPORT V8ContextInfo {
 
   static int executionContextId(v8::Local<v8::Context> context);
 
+ private:
   // Disallow copying and allocating this one.
   enum NotNullTagEnum { NotNullLiteral };
   void* operator new(size_t) = delete;
@@ -130,11 +131,7 @@ class V8_EXPORT V8InspectorSession {
   // Dispatching protocol messages.
   static bool canDispatchMethod(const StringView& method);
   virtual void dispatchProtocolMessage(const StringView& message) = 0;
-  virtual V8_DEPRECATED("Use state() instead",
-                        std::unique_ptr<StringBuffer> stateJSON()) {
-    return nullptr;
-  }
-  virtual std::vector<uint8_t> state() = 0;
+  virtual std::unique_ptr<StringBuffer> stateJSON() = 0;
   virtual std::vector<std::unique_ptr<protocol::Schema::API::Domain>>
   supportedDomains() = 0;
 
diff --git a/ios/include/v8/v8-internal.h b/ios/include/v8/v8-internal.h
index ef13006d..8e700a4d 100644
--- a/ios/include/v8/v8-internal.h
+++ b/ios/include/v8/v8-internal.h
@@ -48,32 +48,28 @@ const intptr_t kSmiTagMask = (1 << kSmiTagSize) - 1;
 template <size_t tagged_ptr_size>
 struct SmiTagging;
 
-constexpr intptr_t kIntptrAllBitsSet = intptr_t{-1};
-constexpr uintptr_t kUintptrAllBitsSet =
-    static_cast<uintptr_t>(kIntptrAllBitsSet);
-
 // Smi constants for systems where tagged pointer is a 32-bit value.
 template <>
 struct SmiTagging<4> {
   enum { kSmiShiftSize = 0, kSmiValueSize = 31 };
-
-  static constexpr intptr_t kSmiMinValue =
-      static_cast<intptr_t>(kUintptrAllBitsSet << (kSmiValueSize - 1));
-  static constexpr intptr_t kSmiMaxValue = -(kSmiMinValue + 1);
-
   V8_INLINE static int SmiToInt(const internal::Address value) {
     int shift_bits = kSmiTagSize + kSmiShiftSize;
     // Shift down (requires >> to be sign extending).
     return static_cast<int>(static_cast<intptr_t>(value)) >> shift_bits;
   }
   V8_INLINE static constexpr bool IsValidSmi(intptr_t value) {
-    // Is value in range [kSmiMinValue, kSmiMaxValue].
-    // Use unsigned operations in order to avoid undefined behaviour in case of
-    // signed integer overflow.
-    return (static_cast<uintptr_t>(value) -
-            static_cast<uintptr_t>(kSmiMinValue)) <=
-           (static_cast<uintptr_t>(kSmiMaxValue) -
-            static_cast<uintptr_t>(kSmiMinValue));
+    // To be representable as an tagged small integer, the two
+    // most-significant bits of 'value' must be either 00 or 11 due to
+    // sign-extension. To check this we add 01 to the two
+    // most-significant bits, and check if the most-significant bit is 0.
+    //
+    // CAUTION: The original code below:
+    // bool result = ((value + 0x40000000) & 0x80000000) == 0;
+    // may lead to incorrect results according to the C language spec, and
+    // in fact doesn't work correctly with gcc4.1.1 in some cases: The
+    // compiler may produce undefined results in case of signed integer
+    // overflow. The computation must be done w/ unsigned ints.
+    return static_cast<uintptr_t>(value) + 0x40000000U < 0x80000000U;
   }
 };
 
@@ -81,11 +77,6 @@ struct SmiTagging<4> {
 template <>
 struct SmiTagging<8> {
   enum { kSmiShiftSize = 31, kSmiValueSize = 32 };
-
-  static constexpr intptr_t kSmiMinValue =
-      static_cast<intptr_t>(kUintptrAllBitsSet << (kSmiValueSize - 1));
-  static constexpr intptr_t kSmiMaxValue = -(kSmiMinValue + 1);
-
   V8_INLINE static int SmiToInt(const internal::Address value) {
     int shift_bits = kSmiTagSize + kSmiShiftSize;
     // Shift down and throw away top 32 bits.
@@ -107,15 +98,15 @@ const int kApiTaggedSize = kApiSystemPointerSize;
 #endif
 
 #ifdef V8_31BIT_SMIS_ON_64BIT_ARCH
-using PlatformSmiTagging = SmiTagging<kApiInt32Size>;
+typedef SmiTagging<kApiInt32Size> PlatformSmiTagging;
 #else
-using PlatformSmiTagging = SmiTagging<kApiTaggedSize>;
+typedef SmiTagging<kApiTaggedSize> PlatformSmiTagging;
 #endif
 
 const int kSmiShiftSize = PlatformSmiTagging::kSmiShiftSize;
 const int kSmiValueSize = PlatformSmiTagging::kSmiValueSize;
-const int kSmiMinValue = static_cast<int>(PlatformSmiTagging::kSmiMinValue);
-const int kSmiMaxValue = static_cast<int>(PlatformSmiTagging::kSmiMaxValue);
+const int kSmiMinValue = (static_cast<unsigned int>(-1)) << (kSmiValueSize - 1);
+const int kSmiMaxValue = -(kSmiMinValue + 1);
 constexpr bool SmiValuesAre31Bits() { return kSmiValueSize == 31; }
 constexpr bool SmiValuesAre32Bits() { return kSmiValueSize == 32; }
 
@@ -174,6 +165,8 @@ class Internals {
   static const int kNodeStateMask = 0x7;
   static const int kNodeStateIsWeakValue = 2;
   static const int kNodeStateIsPendingValue = 3;
+  static const int kNodeIsIndependentShift = 3;
+  static const int kNodeIsActiveShift = 4;
 
   static const int kFirstNonstringType = 0x40;
   static const int kOddballType = 0x43;
diff --git a/ios/include/v8/v8-platform.h b/ios/include/v8/v8-platform.h
index b707fafc..556407d8 100644
--- a/ios/include/v8/v8-platform.h
+++ b/ios/include/v8/v8-platform.h
@@ -109,6 +109,7 @@ class TaskRunner {
   TaskRunner() = default;
   virtual ~TaskRunner() = default;
 
+ private:
   TaskRunner(const TaskRunner&) = delete;
   TaskRunner& operator=(const TaskRunner&) = delete;
 };
diff --git a/ios/include/v8/v8-profiler.h b/ios/include/v8/v8-profiler.h
index 46d3eb8a..672a694e 100644
--- a/ios/include/v8/v8-profiler.h
+++ b/ios/include/v8/v8-profiler.h
@@ -5,7 +5,6 @@
 #ifndef V8_V8_PROFILER_H_
 #define V8_V8_PROFILER_H_
 
-#include <limits.h>
 #include <unordered_set>
 #include <vector>
 #include "v8.h"  // NOLINT(build/include)
@@ -298,53 +297,6 @@ enum CpuProfilingMode {
   kCallerLineNumbers,
 };
 
-// Determines how names are derived for functions sampled.
-enum CpuProfilingNamingMode {
-  // Use the immediate name of functions at compilation time.
-  kStandardNaming,
-  // Use more verbose naming for functions without names, inferred from scope
-  // where possible.
-  kDebugNaming,
-};
-
-/**
- * Optional profiling attributes.
- */
-class V8_EXPORT CpuProfilingOptions {
- public:
-  // Indicates that the sample buffer size should not be explicitly limited.
-  static const unsigned kNoSampleLimit = UINT_MAX;
-
-  /**
-   * \param mode Type of computation of stack frame line numbers.
-   * \param max_samples The maximum number of samples that should be recorded by
-   *                    the profiler. Samples obtained after this limit will be
-   *                    discarded.
-   * \param sampling_interval_us controls the profile-specific target
-   *                             sampling interval. The provided sampling
-   *                             interval will be snapped to the next lowest
-   *                             non-zero multiple of the profiler's sampling
-   *                             interval, set via SetSamplingInterval(). If
-   *                             zero, the sampling interval will be equal to
-   *                             the profiler's sampling interval.
-   */
-  CpuProfilingOptions(CpuProfilingMode mode = kLeafNodeLineNumbers,
-                      unsigned max_samples = kNoSampleLimit,
-                      int sampling_interval_us = 0)
-      : mode_(mode),
-        max_samples_(max_samples),
-        sampling_interval_us_(sampling_interval_us) {}
-
-  CpuProfilingMode mode() const { return mode_; }
-  unsigned max_samples() const { return max_samples_; }
-  int sampling_interval_us() const { return sampling_interval_us_; }
-
- private:
-  CpuProfilingMode mode_;
-  unsigned max_samples_;
-  int sampling_interval_us_;
-};
-
 /**
  * Interface for controlling CPU profiling. Instance of the
  * profiler can be created using v8::CpuProfiler::New method.
@@ -356,8 +308,7 @@ class V8_EXPORT CpuProfiler {
    * initialized. The profiler object must be disposed after use by calling
    * |Dispose| method.
    */
-  static CpuProfiler* New(Isolate* isolate,
-                          CpuProfilingNamingMode = kDebugNaming);
+  static CpuProfiler* New(Isolate* isolate);
 
   /**
    * Synchronously collect current stack sample in all profilers attached to
@@ -388,26 +339,18 @@ class V8_EXPORT CpuProfiler {
   void SetUsePreciseSampling(bool);
 
   /**
-   * Starts collecting a CPU profile. Title may be an empty string. Several
-   * profiles may be collected at once. Attempts to start collecting several
-   * profiles with the same title are silently ignored.
-   */
-  void StartProfiling(Local<String> title, CpuProfilingOptions options);
-
-  /**
-   * Starts profiling with the same semantics as above, except with expanded
-   * parameters.
+   * Starts collecting CPU profile. Title may be an empty string. It
+   * is allowed to have several profiles being collected at
+   * once. Attempts to start collecting several profiles with the same
+   * title are silently ignored. While collecting a profile, functions
+   * from all security contexts are included in it. The token-based
+   * filtering is only performed when querying for a profile.
    *
    * |record_samples| parameter controls whether individual samples should
    * be recorded in addition to the aggregated tree.
-   *
-   * |max_samples| controls the maximum number of samples that should be
-   * recorded by the profiler. Samples obtained after this limit will be
-   * discarded.
    */
-  void StartProfiling(
-      Local<String> title, CpuProfilingMode mode, bool record_samples = false,
-      unsigned max_samples = CpuProfilingOptions::kNoSampleLimit);
+  void StartProfiling(Local<String> title, CpuProfilingMode mode,
+                      bool record_samples = false);
   /**
    * The same as StartProfiling above, but the CpuProfilingMode defaults to
    * kLeafNodeLineNumbers mode, which was the previous default behavior of the
@@ -448,6 +391,7 @@ class V8_EXPORT CpuProfiler {
   CpuProfiler& operator=(const CpuProfiler&);
 };
 
+
 /**
  * HeapSnapshotEdge represents a directed connection between heap
  * graph nodes: from retainers to retained nodes.
@@ -798,6 +742,7 @@ class V8_EXPORT EmbedderGraph {
      */
     virtual const char* NamePrefix() { return nullptr; }
 
+   private:
     Node(const Node&) = delete;
     Node& operator=(const Node&) = delete;
   };
diff --git a/ios/include/v8/v8-util.h b/ios/include/v8/v8-util.h
index 29d813e4..24962607 100644
--- a/ios/include/v8/v8-util.h
+++ b/ios/include/v8/v8-util.h
@@ -194,6 +194,14 @@ class PersistentValueMapBase {
     return SetReturnValueFromVal(&returnValue, Traits::Get(&impl_, key));
   }
 
+  /**
+   * Call V8::RegisterExternallyReferencedObject with the map value for given
+   * key.
+   */
+  V8_DEPRECATED(
+      "Used TracedGlobal and EmbedderHeapTracer::RegisterEmbedderReference",
+      inline void RegisterExternallyReferencedObject(K& key));
+
   /**
    * Return value for key and remove it from the map.
    */
@@ -344,6 +352,16 @@ class PersistentValueMapBase {
   const char* label_;
 };
 
+template <typename K, typename V, typename Traits>
+inline void
+PersistentValueMapBase<K, V, Traits>::RegisterExternallyReferencedObject(
+    K& key) {
+  assert(Contains(key));
+  V8::RegisterExternallyReferencedObject(
+      reinterpret_cast<internal::Address*>(FromVal(Traits::Get(&impl_, key))),
+      reinterpret_cast<internal::Isolate*>(GetIsolate()));
+}
+
 template <typename K, typename V, typename Traits>
 class PersistentValueMap : public PersistentValueMapBase<K, V, Traits> {
  public:
diff --git a/ios/include/v8/v8-version.h b/ios/include/v8/v8-version.h
index 21f0a793..dfcd5b46 100644
--- a/ios/include/v8/v8-version.h
+++ b/ios/include/v8/v8-version.h
@@ -9,12 +9,12 @@
 // NOTE these macros are used by some of the tool scripts and the build
 // system so their names cannot be changed without changing the scripts.
 #define V8_MAJOR_VERSION 7
-#define V8_MINOR_VERSION 6
-#define V8_BUILD_NUMBER 0
-#define V8_PATCH_LEVEL 0
+#define V8_MINOR_VERSION 5
+#define V8_BUILD_NUMBER 288
+#define V8_PATCH_LEVEL 22
 
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)
-#define V8_IS_CANDIDATE_VERSION 1
+#define V8_IS_CANDIDATE_VERSION 0
 
 #endif  // V8_INCLUDE_VERSION_H_
diff --git a/ios/include/v8/v8.h b/ios/include/v8/v8.h
index c54b0884..b4b92055 100644
--- a/ios/include/v8/v8.h
+++ b/ios/include/v8/v8.h
@@ -122,6 +122,7 @@ class ExternalString;
 class Isolate;
 class LocalEmbedderHeapTracer;
 class MicrotaskQueue;
+class NeverReadOnlySpaceObject;
 struct ScriptStreamingData;
 template<typename T> class CustomArguments;
 class PropertyCallbackArguments;
@@ -544,6 +545,38 @@ template <class T> class PersistentBase {
    */
   V8_INLINE void AnnotateStrongRetainer(const char* label);
 
+  /**
+   * Allows the embedder to tell the v8 garbage collector that a certain object
+   * is alive. Only allowed when the embedder is asked to trace its heap by
+   * EmbedderHeapTracer.
+   */
+  V8_DEPRECATED(
+      "Used TracedGlobal and EmbedderHeapTracer::RegisterEmbedderReference",
+      V8_INLINE void RegisterExternalReference(Isolate* isolate) const);
+
+  /**
+   * Marks the reference to this object independent. Garbage collector is free
+   * to ignore any object groups containing this object. Weak callback for an
+   * independent handle should not assume that it will be preceded by a global
+   * GC prologue callback or followed by a global GC epilogue callback.
+   */
+  V8_DEPRECATED(
+      "Weak objects are always considered independent. "
+      "Use TracedGlobal when trying to use EmbedderHeapTracer. "
+      "Use a strong handle when trying to keep an object alive.",
+      V8_INLINE void MarkIndependent());
+
+  /**
+   * Marks the reference to this object as active. The scavenge garbage
+   * collection should not reclaim the objects marked as active, even if the
+   * object held by the handle is otherwise unreachable.
+   *
+   * This bit is cleared after the each garbage collection pass.
+   */
+  V8_DEPRECATED("Use TracedGlobal.", V8_INLINE void MarkActive());
+
+  V8_DEPRECATED("See MarkIndependent.", V8_INLINE bool IsIndependent() const);
+
   /** Returns true if the handle's reference is weak.  */
   V8_INLINE bool IsWeak() const;
 
@@ -1900,11 +1933,6 @@ class V8_EXPORT StackFrame {
    * Returns whether or not the associated functions is defined in wasm.
    */
   bool IsWasm() const;
-
-  /**
-   * Returns whether or not the associated function is defined by the user.
-   */
-  bool IsUserJavaScript() const;
 };
 
 
@@ -1923,11 +1951,10 @@ enum StateTag {
 // A RegisterState represents the current state of registers used
 // by the sampling profiler API.
 struct RegisterState {
-  RegisterState() : pc(nullptr), sp(nullptr), fp(nullptr), lr(nullptr) {}
+  RegisterState() : pc(nullptr), sp(nullptr), fp(nullptr) {}
   void* pc;  // Instruction pointer.
   void* sp;  // Stack pointer.
   void* fp;  // Frame pointer.
-  void* lr;  // Link register (or nullptr on platforms without a link register).
 };
 
 // The output structure filled up by GetStackSample API function.
@@ -2093,10 +2120,10 @@ class V8_EXPORT ValueSerializer {
   void WriteDouble(double value);
   void WriteRawBytes(const void* source, size_t length);
 
+ private:
   ValueSerializer(const ValueSerializer&) = delete;
   void operator=(const ValueSerializer&) = delete;
 
- private:
   struct PrivateData;
   PrivateData* private_;
 };
@@ -2195,10 +2222,10 @@ class V8_EXPORT ValueDeserializer {
   V8_WARN_UNUSED_RESULT bool ReadDouble(double* value);
   V8_WARN_UNUSED_RESULT bool ReadRawBytes(size_t length, const void** data);
 
+ private:
   ValueDeserializer(const ValueDeserializer&) = delete;
   void operator=(const ValueDeserializer&) = delete;
 
- private:
   struct PrivateData;
   PrivateData* private_;
 };
@@ -2493,6 +2520,9 @@ class V8_EXPORT Value : public Data {
 
   V8_WARN_UNUSED_RESULT MaybeLocal<BigInt> ToBigInt(
       Local<Context> context) const;
+  V8_DEPRECATED("ToBoolean can never throw. Use Local version.",
+                V8_WARN_UNUSED_RESULT MaybeLocal<Boolean> ToBoolean(
+                    Local<Context> context) const);
   V8_WARN_UNUSED_RESULT MaybeLocal<Number> ToNumber(
       Local<Context> context) const;
   V8_WARN_UNUSED_RESULT MaybeLocal<String> ToString(
@@ -2508,6 +2538,16 @@ class V8_EXPORT Value : public Data {
   V8_WARN_UNUSED_RESULT MaybeLocal<Int32> ToInt32(Local<Context> context) const;
 
   Local<Boolean> ToBoolean(Isolate* isolate) const;
+  V8_DEPRECATED("Use maybe version",
+                Local<Number> ToNumber(Isolate* isolate) const);
+  V8_DEPRECATED("Use maybe version",
+                Local<String> ToString(Isolate* isolate) const);
+  V8_DEPRECATED("Use maybe version",
+                Local<Object> ToObject(Isolate* isolate) const);
+  V8_DEPRECATED("Use maybe version",
+                Local<Integer> ToInteger(Isolate* isolate) const);
+  V8_DEPRECATED("Use maybe version",
+                Local<Int32> ToInt32(Isolate* isolate) const);
 
   /**
    * Attempts to convert a string to an array index.
@@ -2518,6 +2558,9 @@ class V8_EXPORT Value : public Data {
 
   bool BooleanValue(Isolate* isolate) const;
 
+  V8_DEPRECATED("BooleanValue can never throw. Use Isolate version.",
+                V8_WARN_UNUSED_RESULT Maybe<bool> BooleanValue(
+                    Local<Context> context) const);
   V8_WARN_UNUSED_RESULT Maybe<double> NumberValue(Local<Context> context) const;
   V8_WARN_UNUSED_RESULT Maybe<int64_t> IntegerValue(
       Local<Context> context) const;
@@ -2721,10 +2764,6 @@ class V8_EXPORT String : public Name {
      */
     virtual bool IsCacheable() const { return true; }
 
-    // Disallow copying and assigning.
-    ExternalStringResourceBase(const ExternalStringResourceBase&) = delete;
-    void operator=(const ExternalStringResourceBase&) = delete;
-
    protected:
     ExternalStringResourceBase() = default;
 
@@ -2754,6 +2793,10 @@ class V8_EXPORT String : public Name {
      */
     virtual void Unlock() const {}
 
+    // Disallow copying and assigning.
+    ExternalStringResourceBase(const ExternalStringResourceBase&) = delete;
+    void operator=(const ExternalStringResourceBase&) = delete;
+
    private:
     friend class internal::ExternalString;
     friend class v8::String;
@@ -2837,23 +2880,43 @@ class V8_EXPORT String : public Name {
 
   V8_INLINE static String* Cast(v8::Value* obj);
 
+  // TODO(dcarney): remove with deprecation of New functions.
+  enum NewStringType {
+    kNormalString = static_cast<int>(v8::NewStringType::kNormal),
+    kInternalizedString = static_cast<int>(v8::NewStringType::kInternalized)
+  };
+
+  /** Allocates a new string from UTF-8 data.*/
+  static V8_DEPRECATED(
+      "Use maybe version",
+      Local<String> NewFromUtf8(Isolate* isolate, const char* data,
+                                NewStringType type = kNormalString,
+                                int length = -1));
+
   /** Allocates a new string from UTF-8 data. Only returns an empty value when
    * length > kMaxLength. **/
   static V8_WARN_UNUSED_RESULT MaybeLocal<String> NewFromUtf8(
-      Isolate* isolate, const char* data,
-      NewStringType type = NewStringType::kNormal, int length = -1);
+      Isolate* isolate, const char* data, v8::NewStringType type,
+      int length = -1);
 
   /** Allocates a new string from Latin-1 data.  Only returns an empty value
    * when length > kMaxLength. **/
   static V8_WARN_UNUSED_RESULT MaybeLocal<String> NewFromOneByte(
-      Isolate* isolate, const uint8_t* data,
-      NewStringType type = NewStringType::kNormal, int length = -1);
+      Isolate* isolate, const uint8_t* data, v8::NewStringType type,
+      int length = -1);
+
+  /** Allocates a new string from UTF-16 data.*/
+  static V8_DEPRECATED(
+      "Use maybe version",
+      Local<String> NewFromTwoByte(Isolate* isolate, const uint16_t* data,
+                                   NewStringType type = kNormalString,
+                                   int length = -1));
 
   /** Allocates a new string from UTF-16 data. Only returns an empty value when
    * length > kMaxLength. **/
   static V8_WARN_UNUSED_RESULT MaybeLocal<String> NewFromTwoByte(
-      Isolate* isolate, const uint16_t* data,
-      NewStringType type = NewStringType::kNormal, int length = -1);
+      Isolate* isolate, const uint16_t* data, v8::NewStringType type,
+      int length = -1);
 
   /**
    * Creates a new string by concatenating the left and the right strings
@@ -2892,6 +2955,10 @@ class V8_EXPORT String : public Name {
    * should the underlying buffer be deallocated or modified except through the
    * destructor of the external string resource.
    */
+  static V8_DEPRECATED(
+      "Use maybe version",
+      Local<String> NewExternal(Isolate* isolate,
+                                ExternalOneByteStringResource* resource));
   static V8_WARN_UNUSED_RESULT MaybeLocal<String> NewExternalOneByte(
       Isolate* isolate, ExternalOneByteStringResource* resource);
 
@@ -3288,8 +3355,8 @@ enum class IntegrityLevel { kFrozen, kSealed };
  */
 class V8_EXPORT Object : public Value {
  public:
-  V8_DEPRECATED("Use maybe version",
-                bool Set(Local<Value> key, Local<Value> value));
+  V8_DEPRECATE_SOON("Use maybe version",
+                    bool Set(Local<Value> key, Local<Value> value));
   /**
    * Set only return Just(true) or Empty(), so if it should never fail, use
    * result.Check().
@@ -3297,8 +3364,8 @@ class V8_EXPORT Object : public Value {
   V8_WARN_UNUSED_RESULT Maybe<bool> Set(Local<Context> context,
                                         Local<Value> key, Local<Value> value);
 
-  V8_DEPRECATED("Use maybe version",
-                bool Set(uint32_t index, Local<Value> value));
+  V8_DEPRECATE_SOON("Use maybe version",
+                    bool Set(uint32_t index, Local<Value> value));
   V8_WARN_UNUSED_RESULT Maybe<bool> Set(Local<Context> context, uint32_t index,
                                         Local<Value> value);
 
@@ -3342,11 +3409,11 @@ class V8_EXPORT Object : public Value {
   V8_WARN_UNUSED_RESULT Maybe<bool> DefineProperty(
       Local<Context> context, Local<Name> key, PropertyDescriptor& descriptor);
 
-  V8_DEPRECATED("Use maybe version", Local<Value> Get(Local<Value> key));
+  V8_DEPRECATE_SOON("Use maybe version", Local<Value> Get(Local<Value> key));
   V8_WARN_UNUSED_RESULT MaybeLocal<Value> Get(Local<Context> context,
                                               Local<Value> key);
 
-  V8_DEPRECATED("Use maybe version", Local<Value> Get(uint32_t index));
+  V8_DEPRECATE_SOON("Use maybe version", Local<Value> Get(uint32_t index));
   V8_WARN_UNUSED_RESULT MaybeLocal<Value> Get(Local<Context> context,
                                               uint32_t index);
 
@@ -3830,6 +3897,9 @@ class ReturnValue {
   }
   // Local setters
   template <typename S>
+  V8_INLINE V8_DEPRECATED("Use Global<> instead",
+                          void Set(const Persistent<S>& handle));
+  template <typename S>
   V8_INLINE void Set(const Global<S>& handle);
   template <typename S>
   V8_INLINE void Set(const TracedGlobal<S>& handle);
@@ -5217,6 +5287,38 @@ class V8_EXPORT Date : public Object {
 
   V8_INLINE static Date* Cast(Value* obj);
 
+  /**
+   * Time zone redetection indicator for
+   * DateTimeConfigurationChangeNotification.
+   *
+   * kSkip indicates V8 that the notification should not trigger redetecting
+   * host time zone. kRedetect indicates V8 that host time zone should be
+   * redetected, and used to set the default time zone.
+   *
+   * The host time zone detection may require file system access or similar
+   * operations unlikely to be available inside a sandbox. If v8 is run inside a
+   * sandbox, the host time zone has to be detected outside the sandbox before
+   * calling DateTimeConfigurationChangeNotification function.
+   */
+  enum class TimeZoneDetection { kSkip, kRedetect };
+
+  /**
+   * Notification that the embedder has changed the time zone,
+   * daylight savings time, or other date / time configuration
+   * parameters.  V8 keeps a cache of various values used for
+   * date / time computation.  This notification will reset
+   * those cached values for the current context so that date /
+   * time configuration changes would be reflected in the Date
+   * object.
+   *
+   * This API should not be called more than needed as it will
+   * negatively impact the performance of date operations.
+   */
+  V8_DEPRECATED("Use Isolate::DateTimeConfigurationChangeNotification",
+                static void DateTimeConfigurationChangeNotification(
+                    Isolate* isolate, TimeZoneDetection time_zone_detection =
+                                          TimeZoneDetection::kSkip));
+
  private:
   static void CheckCast(Value* obj);
 };
@@ -5902,6 +6004,21 @@ class V8_EXPORT FunctionTemplate : public Template {
    */
   void SetAcceptAnyReceiver(bool value);
 
+  /**
+   * Determines whether the __proto__ accessor ignores instances of
+   * the function template.  If instances of the function template are
+   * ignored, __proto__ skips all instances and instead returns the
+   * next object in the prototype chain.
+   *
+   * Call with a value of true to make the __proto__ accessor ignore
+   * instances of the function template.  Call with a value of false
+   * to make the __proto__ accessor not ignore instances of the
+   * function template.  By default, instances of a function template
+   * are not ignored.
+   */
+  V8_DEPRECATED("This feature is incompatible with ES6+.",
+                void SetHiddenPrototype(bool value));
+
   /**
    * Sets the ReadOnly flag in the attributes of the 'prototype' property
    * of functions created from this FunctionTemplate to true.
@@ -6706,12 +6823,11 @@ class V8_EXPORT MicrotaskQueue {
    */
   virtual int GetMicrotasksScopeDepth() const = 0;
 
-  MicrotaskQueue(const MicrotaskQueue&) = delete;
-  MicrotaskQueue& operator=(const MicrotaskQueue&) = delete;
-
  private:
   friend class internal::MicrotaskQueue;
   MicrotaskQueue() = default;
+  MicrotaskQueue(const MicrotaskQueue&) = delete;
+  MicrotaskQueue& operator=(const MicrotaskQueue&) = delete;
 };
 
 /**
@@ -7102,11 +7218,6 @@ enum class MemoryPressureLevel { kNone, kModerate, kCritical };
  */
 class V8_EXPORT EmbedderHeapTracer {
  public:
-  enum TraceFlags : uint64_t {
-    kNoFlags = 0,
-    kReduceMemory = 1 << 0,
-  };
-
   // Indicator for the stack state of the embedder.
   enum EmbedderStackState {
     kUnknown,
@@ -7123,24 +7234,6 @@ class V8_EXPORT EmbedderHeapTracer {
     virtual void VisitTracedGlobalHandle(const TracedGlobal<Value>& value) = 0;
   };
 
-  /**
-   * Summary of a garbage collection cycle. See |TraceEpilogue| on how the
-   * summary is reported.
-   */
-  struct TraceSummary {
-    /**
-     * Time spent managing the retained memory in milliseconds. This can e.g.
-     * include the time tracing through objects in the embedder.
-     */
-    double time = 0.0;
-
-    /**
-     * Memory retained by the embedder through the |EmbedderHeapTracer|
-     * mechanism in bytes.
-     */
-    size_t allocated_size = 0;
-  };
-
   virtual ~EmbedderHeapTracer() = default;
 
   /**
@@ -7163,8 +7256,7 @@ class V8_EXPORT EmbedderHeapTracer {
   /**
    * Called at the beginning of a GC cycle.
    */
-  V8_DEPRECATE_SOON("Use version with flags.", virtual void TracePrologue()) {}
-  virtual void TracePrologue(TraceFlags flags);
+  virtual void TracePrologue() = 0;
 
   /**
    * Called to advance tracing in the embedder.
@@ -7187,12 +7279,9 @@ class V8_EXPORT EmbedderHeapTracer {
   /**
    * Called at the end of a GC cycle.
    *
-   * Note that allocation is *not* allowed within |TraceEpilogue|. Can be
-   * overriden to fill a |TraceSummary| that is used by V8 to schedule future
-   * garbage collections.
+   * Note that allocation is *not* allowed within |TraceEpilogue|.
    */
-  virtual void TraceEpilogue() {}
-  virtual void TraceEpilogue(TraceSummary* trace_summary) { TraceEpilogue(); }
+  virtual void TraceEpilogue() = 0;
 
   /**
    * Called upon entering the final marking pause. No more incremental marking
@@ -7229,14 +7318,6 @@ class V8_EXPORT EmbedderHeapTracer {
    */
   void GarbageCollectionForTesting(EmbedderStackState stack_state);
 
-  /*
-   * Called by the embedder to signal newly allocated memory. Not bound to
-   * tracing phases. Embedders should trade off when increments are reported as
-   * V8 may consult global heuristics on whether to trigger garbage collection
-   * on this change.
-   */
-  void IncreaseAllocatedSize(size_t bytes);
-
   /*
    * Returns the v8::Isolate this tracer is attached too and |nullptr| if it
    * is not attached to any v8::Isolate.
@@ -8529,13 +8610,6 @@ class V8_EXPORT Isolate {
 
 class V8_EXPORT StartupData {
  public:
-  /**
-   * Whether the data created can be rehashed and and the hash seed can be
-   * recomputed when deserialized.
-   * Only valid for StartupData returned by SnapshotCreator::CreateBlob().
-   */
-  bool CanBeRehashed() const;
-
   const char* data;
   int raw_size;
 };
@@ -8594,10 +8668,7 @@ class V8_EXPORT V8 {
   /**
    * Sets V8 flags from a string.
    */
-  static void SetFlagsFromString(const char* str);
-  static void SetFlagsFromString(const char* str, size_t length);
-  V8_DEPRECATED("use size_t version",
-                static void SetFlagsFromString(const char* str, int length));
+  static void SetFlagsFromString(const char* str, int length);
 
   /**
    * Sets V8 flags from the command line.
@@ -8768,6 +8839,9 @@ class V8_EXPORT V8 {
                                      const char* label);
   static Value* Eternalize(Isolate* isolate, Value* handle);
 
+  static void RegisterExternallyReferencedObject(internal::Address* location,
+                                                 internal::Isolate* isolate);
+
   template <class K, class V, class T>
   friend class PersistentValueMapBase;
 
@@ -9714,6 +9788,14 @@ void Persistent<T, M>::Copy(const Persistent<S, M2>& that) {
   M::Copy(that, this);
 }
 
+template <class T>
+bool PersistentBase<T>::IsIndependent() const {
+  typedef internal::Internals I;
+  if (this->IsEmpty()) return false;
+  return I::GetNodeFlag(reinterpret_cast<internal::Address*>(this->val_),
+                        I::kNodeIsIndependentShift);
+}
+
 template <class T>
 bool PersistentBase<T>::IsWeak() const {
   typedef internal::Internals I;
@@ -9780,6 +9862,31 @@ void PersistentBase<T>::AnnotateStrongRetainer(const char* label) {
                              label);
 }
 
+template <class T>
+void PersistentBase<T>::RegisterExternalReference(Isolate* isolate) const {
+  if (IsEmpty()) return;
+  V8::RegisterExternallyReferencedObject(
+      reinterpret_cast<internal::Address*>(this->val_),
+      reinterpret_cast<internal::Isolate*>(isolate));
+}
+
+template <class T>
+void PersistentBase<T>::MarkIndependent() {
+  typedef internal::Internals I;
+  if (this->IsEmpty()) return;
+  I::UpdateNodeFlag(reinterpret_cast<internal::Address*>(this->val_), true,
+                    I::kNodeIsIndependentShift);
+}
+
+template <class T>
+void PersistentBase<T>::MarkActive() {
+  typedef internal::Internals I;
+  if (this->IsEmpty()) return;
+  I::UpdateNodeFlag(reinterpret_cast<internal::Address*>(this->val_), true,
+                    I::kNodeIsActiveShift);
+}
+
+
 template <class T>
 void PersistentBase<T>::SetWrapperClassId(uint16_t class_id) {
   typedef internal::Internals I;
@@ -9905,6 +10012,17 @@ void TracedGlobal<T>::SetFinalizationCallback(
 template <typename T>
 ReturnValue<T>::ReturnValue(internal::Address* slot) : value_(slot) {}
 
+template<typename T>
+template<typename S>
+void ReturnValue<T>::Set(const Persistent<S>& handle) {
+  TYPE_CHECK(T, S);
+  if (V8_UNLIKELY(handle.IsEmpty())) {
+    *value_ = GetDefaultValue();
+  } else {
+    *value_ = *reinterpret_cast<internal::Address*>(*handle);
+  }
+}
+
 template <typename T>
 template <typename S>
 void ReturnValue<T>::Set(const Global<S>& handle) {
@@ -10824,8 +10942,7 @@ int64_t Isolate::AdjustAmountOfExternalAllocatedMemory(
   *external_memory = amount;
 
   int64_t allocation_diff_since_last_mc =
-      static_cast<int64_t>(static_cast<uint64_t>(*external_memory) -
-                           static_cast<uint64_t>(*external_memory_at_last_mc));
+      *external_memory - *external_memory_at_last_mc;
   // Only check memory pressure and potentially trigger GC if the amount of
   // external memory increased.
   if (allocation_diff_since_last_mc > kMemoryReducerActivationLimit) {
diff --git a/mac/include/v8/libplatform/DEPS b/mac/include/v8/libplatform/DEPS
deleted file mode 100644
index d8bcf998..00000000
--- a/mac/include/v8/libplatform/DEPS
+++ /dev/null
@@ -1,9 +0,0 @@
-include_rules = [
-  "+libplatform/libplatform-export.h",
-]
-
-specific_include_rules = {
-  "libplatform\.h": [
-    "+libplatform/v8-tracing.h",
-  ],
-}
diff --git a/mac/include/v8/libplatform/v8-tracing.h b/mac/include/v8/libplatform/v8-tracing.h
index 0eb7f4be..bc249cb9 100644
--- a/mac/include/v8/libplatform/v8-tracing.h
+++ b/mac/include/v8/libplatform/v8-tracing.h
@@ -23,8 +23,6 @@ class Mutex;
 namespace platform {
 namespace tracing {
 
-class PerfettoTracingController;
-
 const int kTraceMaxNumArgs = 2;
 
 class V8_PLATFORM_EXPORT TraceObject {
@@ -240,11 +238,6 @@ class V8_PLATFORM_EXPORT TracingController
   TracingController();
   ~TracingController() override;
   void Initialize(TraceBuffer* trace_buffer);
-#ifdef V8_USE_PERFETTO
-  // Must be called before StartTracing() if V8_USE_PERFETTO is true. Provides
-  // the output stream for the JSON trace data.
-  void InitializeForPerfetto(std::ostream* output_stream);
-#endif
 
   // v8::TracingController implementation.
   const uint8_t* GetCategoryGroupEnabled(const char* category_group) override;
@@ -287,11 +280,6 @@ class V8_PLATFORM_EXPORT TracingController
   std::unique_ptr<base::Mutex> mutex_;
   std::unordered_set<v8::TracingController::TraceStateObserver*> observers_;
   std::atomic_bool recording_{false};
-#ifdef V8_USE_PERFETTO
-  std::atomic_bool perfetto_recording_{false};
-  std::unique_ptr<PerfettoTracingController> perfetto_tracing_controller_;
-  std::ostream* output_stream_ = nullptr;
-#endif
 
   // Disallow copy and assign
   TracingController(const TracingController&) = delete;
diff --git a/mac/include/v8/v8-inspector.h b/mac/include/v8/v8-inspector.h
index b96a6e29..70201358 100644
--- a/mac/include/v8/v8-inspector.h
+++ b/mac/include/v8/v8-inspector.h
@@ -87,6 +87,7 @@ class V8_EXPORT V8ContextInfo {
 
   static int executionContextId(v8::Local<v8::Context> context);
 
+ private:
   // Disallow copying and allocating this one.
   enum NotNullTagEnum { NotNullLiteral };
   void* operator new(size_t) = delete;
@@ -130,11 +131,7 @@ class V8_EXPORT V8InspectorSession {
   // Dispatching protocol messages.
   static bool canDispatchMethod(const StringView& method);
   virtual void dispatchProtocolMessage(const StringView& message) = 0;
-  virtual V8_DEPRECATED("Use state() instead",
-                        std::unique_ptr<StringBuffer> stateJSON()) {
-    return nullptr;
-  }
-  virtual std::vector<uint8_t> state() = 0;
+  virtual std::unique_ptr<StringBuffer> stateJSON() = 0;
   virtual std::vector<std::unique_ptr<protocol::Schema::API::Domain>>
   supportedDomains() = 0;
 
diff --git a/mac/include/v8/v8-internal.h b/mac/include/v8/v8-internal.h
index ef13006d..8e700a4d 100644
--- a/mac/include/v8/v8-internal.h
+++ b/mac/include/v8/v8-internal.h
@@ -48,32 +48,28 @@ const intptr_t kSmiTagMask = (1 << kSmiTagSize) - 1;
 template <size_t tagged_ptr_size>
 struct SmiTagging;
 
-constexpr intptr_t kIntptrAllBitsSet = intptr_t{-1};
-constexpr uintptr_t kUintptrAllBitsSet =
-    static_cast<uintptr_t>(kIntptrAllBitsSet);
-
 // Smi constants for systems where tagged pointer is a 32-bit value.
 template <>
 struct SmiTagging<4> {
   enum { kSmiShiftSize = 0, kSmiValueSize = 31 };
-
-  static constexpr intptr_t kSmiMinValue =
-      static_cast<intptr_t>(kUintptrAllBitsSet << (kSmiValueSize - 1));
-  static constexpr intptr_t kSmiMaxValue = -(kSmiMinValue + 1);
-
   V8_INLINE static int SmiToInt(const internal::Address value) {
     int shift_bits = kSmiTagSize + kSmiShiftSize;
     // Shift down (requires >> to be sign extending).
     return static_cast<int>(static_cast<intptr_t>(value)) >> shift_bits;
   }
   V8_INLINE static constexpr bool IsValidSmi(intptr_t value) {
-    // Is value in range [kSmiMinValue, kSmiMaxValue].
-    // Use unsigned operations in order to avoid undefined behaviour in case of
-    // signed integer overflow.
-    return (static_cast<uintptr_t>(value) -
-            static_cast<uintptr_t>(kSmiMinValue)) <=
-           (static_cast<uintptr_t>(kSmiMaxValue) -
-            static_cast<uintptr_t>(kSmiMinValue));
+    // To be representable as an tagged small integer, the two
+    // most-significant bits of 'value' must be either 00 or 11 due to
+    // sign-extension. To check this we add 01 to the two
+    // most-significant bits, and check if the most-significant bit is 0.
+    //
+    // CAUTION: The original code below:
+    // bool result = ((value + 0x40000000) & 0x80000000) == 0;
+    // may lead to incorrect results according to the C language spec, and
+    // in fact doesn't work correctly with gcc4.1.1 in some cases: The
+    // compiler may produce undefined results in case of signed integer
+    // overflow. The computation must be done w/ unsigned ints.
+    return static_cast<uintptr_t>(value) + 0x40000000U < 0x80000000U;
   }
 };
 
@@ -81,11 +77,6 @@ struct SmiTagging<4> {
 template <>
 struct SmiTagging<8> {
   enum { kSmiShiftSize = 31, kSmiValueSize = 32 };
-
-  static constexpr intptr_t kSmiMinValue =
-      static_cast<intptr_t>(kUintptrAllBitsSet << (kSmiValueSize - 1));
-  static constexpr intptr_t kSmiMaxValue = -(kSmiMinValue + 1);
-
   V8_INLINE static int SmiToInt(const internal::Address value) {
     int shift_bits = kSmiTagSize + kSmiShiftSize;
     // Shift down and throw away top 32 bits.
@@ -107,15 +98,15 @@ const int kApiTaggedSize = kApiSystemPointerSize;
 #endif
 
 #ifdef V8_31BIT_SMIS_ON_64BIT_ARCH
-using PlatformSmiTagging = SmiTagging<kApiInt32Size>;
+typedef SmiTagging<kApiInt32Size> PlatformSmiTagging;
 #else
-using PlatformSmiTagging = SmiTagging<kApiTaggedSize>;
+typedef SmiTagging<kApiTaggedSize> PlatformSmiTagging;
 #endif
 
 const int kSmiShiftSize = PlatformSmiTagging::kSmiShiftSize;
 const int kSmiValueSize = PlatformSmiTagging::kSmiValueSize;
-const int kSmiMinValue = static_cast<int>(PlatformSmiTagging::kSmiMinValue);
-const int kSmiMaxValue = static_cast<int>(PlatformSmiTagging::kSmiMaxValue);
+const int kSmiMinValue = (static_cast<unsigned int>(-1)) << (kSmiValueSize - 1);
+const int kSmiMaxValue = -(kSmiMinValue + 1);
 constexpr bool SmiValuesAre31Bits() { return kSmiValueSize == 31; }
 constexpr bool SmiValuesAre32Bits() { return kSmiValueSize == 32; }
 
@@ -174,6 +165,8 @@ class Internals {
   static const int kNodeStateMask = 0x7;
   static const int kNodeStateIsWeakValue = 2;
   static const int kNodeStateIsPendingValue = 3;
+  static const int kNodeIsIndependentShift = 3;
+  static const int kNodeIsActiveShift = 4;
 
   static const int kFirstNonstringType = 0x40;
   static const int kOddballType = 0x43;
diff --git a/mac/include/v8/v8-platform.h b/mac/include/v8/v8-platform.h
index b707fafc..556407d8 100644
--- a/mac/include/v8/v8-platform.h
+++ b/mac/include/v8/v8-platform.h
@@ -109,6 +109,7 @@ class TaskRunner {
   TaskRunner() = default;
   virtual ~TaskRunner() = default;
 
+ private:
   TaskRunner(const TaskRunner&) = delete;
   TaskRunner& operator=(const TaskRunner&) = delete;
 };
diff --git a/mac/include/v8/v8-profiler.h b/mac/include/v8/v8-profiler.h
index 46d3eb8a..672a694e 100644
--- a/mac/include/v8/v8-profiler.h
+++ b/mac/include/v8/v8-profiler.h
@@ -5,7 +5,6 @@
 #ifndef V8_V8_PROFILER_H_
 #define V8_V8_PROFILER_H_
 
-#include <limits.h>
 #include <unordered_set>
 #include <vector>
 #include "v8.h"  // NOLINT(build/include)
@@ -298,53 +297,6 @@ enum CpuProfilingMode {
   kCallerLineNumbers,
 };
 
-// Determines how names are derived for functions sampled.
-enum CpuProfilingNamingMode {
-  // Use the immediate name of functions at compilation time.
-  kStandardNaming,
-  // Use more verbose naming for functions without names, inferred from scope
-  // where possible.
-  kDebugNaming,
-};
-
-/**
- * Optional profiling attributes.
- */
-class V8_EXPORT CpuProfilingOptions {
- public:
-  // Indicates that the sample buffer size should not be explicitly limited.
-  static const unsigned kNoSampleLimit = UINT_MAX;
-
-  /**
-   * \param mode Type of computation of stack frame line numbers.
-   * \param max_samples The maximum number of samples that should be recorded by
-   *                    the profiler. Samples obtained after this limit will be
-   *                    discarded.
-   * \param sampling_interval_us controls the profile-specific target
-   *                             sampling interval. The provided sampling
-   *                             interval will be snapped to the next lowest
-   *                             non-zero multiple of the profiler's sampling
-   *                             interval, set via SetSamplingInterval(). If
-   *                             zero, the sampling interval will be equal to
-   *                             the profiler's sampling interval.
-   */
-  CpuProfilingOptions(CpuProfilingMode mode = kLeafNodeLineNumbers,
-                      unsigned max_samples = kNoSampleLimit,
-                      int sampling_interval_us = 0)
-      : mode_(mode),
-        max_samples_(max_samples),
-        sampling_interval_us_(sampling_interval_us) {}
-
-  CpuProfilingMode mode() const { return mode_; }
-  unsigned max_samples() const { return max_samples_; }
-  int sampling_interval_us() const { return sampling_interval_us_; }
-
- private:
-  CpuProfilingMode mode_;
-  unsigned max_samples_;
-  int sampling_interval_us_;
-};
-
 /**
  * Interface for controlling CPU profiling. Instance of the
  * profiler can be created using v8::CpuProfiler::New method.
@@ -356,8 +308,7 @@ class V8_EXPORT CpuProfiler {
    * initialized. The profiler object must be disposed after use by calling
    * |Dispose| method.
    */
-  static CpuProfiler* New(Isolate* isolate,
-                          CpuProfilingNamingMode = kDebugNaming);
+  static CpuProfiler* New(Isolate* isolate);
 
   /**
    * Synchronously collect current stack sample in all profilers attached to
@@ -388,26 +339,18 @@ class V8_EXPORT CpuProfiler {
   void SetUsePreciseSampling(bool);
 
   /**
-   * Starts collecting a CPU profile. Title may be an empty string. Several
-   * profiles may be collected at once. Attempts to start collecting several
-   * profiles with the same title are silently ignored.
-   */
-  void StartProfiling(Local<String> title, CpuProfilingOptions options);
-
-  /**
-   * Starts profiling with the same semantics as above, except with expanded
-   * parameters.
+   * Starts collecting CPU profile. Title may be an empty string. It
+   * is allowed to have several profiles being collected at
+   * once. Attempts to start collecting several profiles with the same
+   * title are silently ignored. While collecting a profile, functions
+   * from all security contexts are included in it. The token-based
+   * filtering is only performed when querying for a profile.
    *
    * |record_samples| parameter controls whether individual samples should
    * be recorded in addition to the aggregated tree.
-   *
-   * |max_samples| controls the maximum number of samples that should be
-   * recorded by the profiler. Samples obtained after this limit will be
-   * discarded.
    */
-  void StartProfiling(
-      Local<String> title, CpuProfilingMode mode, bool record_samples = false,
-      unsigned max_samples = CpuProfilingOptions::kNoSampleLimit);
+  void StartProfiling(Local<String> title, CpuProfilingMode mode,
+                      bool record_samples = false);
   /**
    * The same as StartProfiling above, but the CpuProfilingMode defaults to
    * kLeafNodeLineNumbers mode, which was the previous default behavior of the
@@ -448,6 +391,7 @@ class V8_EXPORT CpuProfiler {
   CpuProfiler& operator=(const CpuProfiler&);
 };
 
+
 /**
  * HeapSnapshotEdge represents a directed connection between heap
  * graph nodes: from retainers to retained nodes.
@@ -798,6 +742,7 @@ class V8_EXPORT EmbedderGraph {
      */
     virtual const char* NamePrefix() { return nullptr; }
 
+   private:
     Node(const Node&) = delete;
     Node& operator=(const Node&) = delete;
   };
diff --git a/mac/include/v8/v8-util.h b/mac/include/v8/v8-util.h
index 29d813e4..24962607 100644
--- a/mac/include/v8/v8-util.h
+++ b/mac/include/v8/v8-util.h
@@ -194,6 +194,14 @@ class PersistentValueMapBase {
     return SetReturnValueFromVal(&returnValue, Traits::Get(&impl_, key));
   }
 
+  /**
+   * Call V8::RegisterExternallyReferencedObject with the map value for given
+   * key.
+   */
+  V8_DEPRECATED(
+      "Used TracedGlobal and EmbedderHeapTracer::RegisterEmbedderReference",
+      inline void RegisterExternallyReferencedObject(K& key));
+
   /**
    * Return value for key and remove it from the map.
    */
@@ -344,6 +352,16 @@ class PersistentValueMapBase {
   const char* label_;
 };
 
+template <typename K, typename V, typename Traits>
+inline void
+PersistentValueMapBase<K, V, Traits>::RegisterExternallyReferencedObject(
+    K& key) {
+  assert(Contains(key));
+  V8::RegisterExternallyReferencedObject(
+      reinterpret_cast<internal::Address*>(FromVal(Traits::Get(&impl_, key))),
+      reinterpret_cast<internal::Isolate*>(GetIsolate()));
+}
+
 template <typename K, typename V, typename Traits>
 class PersistentValueMap : public PersistentValueMapBase<K, V, Traits> {
  public:
diff --git a/mac/include/v8/v8-version.h b/mac/include/v8/v8-version.h
index 21f0a793..dfcd5b46 100644
--- a/mac/include/v8/v8-version.h
+++ b/mac/include/v8/v8-version.h
@@ -9,12 +9,12 @@
 // NOTE these macros are used by some of the tool scripts and the build
 // system so their names cannot be changed without changing the scripts.
 #define V8_MAJOR_VERSION 7
-#define V8_MINOR_VERSION 6
-#define V8_BUILD_NUMBER 0
-#define V8_PATCH_LEVEL 0
+#define V8_MINOR_VERSION 5
+#define V8_BUILD_NUMBER 288
+#define V8_PATCH_LEVEL 22
 
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)
-#define V8_IS_CANDIDATE_VERSION 1
+#define V8_IS_CANDIDATE_VERSION 0
 
 #endif  // V8_INCLUDE_VERSION_H_
diff --git a/mac/include/v8/v8.h b/mac/include/v8/v8.h
index c54b0884..b4b92055 100644
--- a/mac/include/v8/v8.h
+++ b/mac/include/v8/v8.h
@@ -122,6 +122,7 @@ class ExternalString;
 class Isolate;
 class LocalEmbedderHeapTracer;
 class MicrotaskQueue;
+class NeverReadOnlySpaceObject;
 struct ScriptStreamingData;
 template<typename T> class CustomArguments;
 class PropertyCallbackArguments;
@@ -544,6 +545,38 @@ template <class T> class PersistentBase {
    */
   V8_INLINE void AnnotateStrongRetainer(const char* label);
 
+  /**
+   * Allows the embedder to tell the v8 garbage collector that a certain object
+   * is alive. Only allowed when the embedder is asked to trace its heap by
+   * EmbedderHeapTracer.
+   */
+  V8_DEPRECATED(
+      "Used TracedGlobal and EmbedderHeapTracer::RegisterEmbedderReference",
+      V8_INLINE void RegisterExternalReference(Isolate* isolate) const);
+
+  /**
+   * Marks the reference to this object independent. Garbage collector is free
+   * to ignore any object groups containing this object. Weak callback for an
+   * independent handle should not assume that it will be preceded by a global
+   * GC prologue callback or followed by a global GC epilogue callback.
+   */
+  V8_DEPRECATED(
+      "Weak objects are always considered independent. "
+      "Use TracedGlobal when trying to use EmbedderHeapTracer. "
+      "Use a strong handle when trying to keep an object alive.",
+      V8_INLINE void MarkIndependent());
+
+  /**
+   * Marks the reference to this object as active. The scavenge garbage
+   * collection should not reclaim the objects marked as active, even if the
+   * object held by the handle is otherwise unreachable.
+   *
+   * This bit is cleared after the each garbage collection pass.
+   */
+  V8_DEPRECATED("Use TracedGlobal.", V8_INLINE void MarkActive());
+
+  V8_DEPRECATED("See MarkIndependent.", V8_INLINE bool IsIndependent() const);
+
   /** Returns true if the handle's reference is weak.  */
   V8_INLINE bool IsWeak() const;
 
@@ -1900,11 +1933,6 @@ class V8_EXPORT StackFrame {
    * Returns whether or not the associated functions is defined in wasm.
    */
   bool IsWasm() const;
-
-  /**
-   * Returns whether or not the associated function is defined by the user.
-   */
-  bool IsUserJavaScript() const;
 };
 
 
@@ -1923,11 +1951,10 @@ enum StateTag {
 // A RegisterState represents the current state of registers used
 // by the sampling profiler API.
 struct RegisterState {
-  RegisterState() : pc(nullptr), sp(nullptr), fp(nullptr), lr(nullptr) {}
+  RegisterState() : pc(nullptr), sp(nullptr), fp(nullptr) {}
   void* pc;  // Instruction pointer.
   void* sp;  // Stack pointer.
   void* fp;  // Frame pointer.
-  void* lr;  // Link register (or nullptr on platforms without a link register).
 };
 
 // The output structure filled up by GetStackSample API function.
@@ -2093,10 +2120,10 @@ class V8_EXPORT ValueSerializer {
   void WriteDouble(double value);
   void WriteRawBytes(const void* source, size_t length);
 
+ private:
   ValueSerializer(const ValueSerializer&) = delete;
   void operator=(const ValueSerializer&) = delete;
 
- private:
   struct PrivateData;
   PrivateData* private_;
 };
@@ -2195,10 +2222,10 @@ class V8_EXPORT ValueDeserializer {
   V8_WARN_UNUSED_RESULT bool ReadDouble(double* value);
   V8_WARN_UNUSED_RESULT bool ReadRawBytes(size_t length, const void** data);
 
+ private:
   ValueDeserializer(const ValueDeserializer&) = delete;
   void operator=(const ValueDeserializer&) = delete;
 
- private:
   struct PrivateData;
   PrivateData* private_;
 };
@@ -2493,6 +2520,9 @@ class V8_EXPORT Value : public Data {
 
   V8_WARN_UNUSED_RESULT MaybeLocal<BigInt> ToBigInt(
       Local<Context> context) const;
+  V8_DEPRECATED("ToBoolean can never throw. Use Local version.",
+                V8_WARN_UNUSED_RESULT MaybeLocal<Boolean> ToBoolean(
+                    Local<Context> context) const);
   V8_WARN_UNUSED_RESULT MaybeLocal<Number> ToNumber(
       Local<Context> context) const;
   V8_WARN_UNUSED_RESULT MaybeLocal<String> ToString(
@@ -2508,6 +2538,16 @@ class V8_EXPORT Value : public Data {
   V8_WARN_UNUSED_RESULT MaybeLocal<Int32> ToInt32(Local<Context> context) const;
 
   Local<Boolean> ToBoolean(Isolate* isolate) const;
+  V8_DEPRECATED("Use maybe version",
+                Local<Number> ToNumber(Isolate* isolate) const);
+  V8_DEPRECATED("Use maybe version",
+                Local<String> ToString(Isolate* isolate) const);
+  V8_DEPRECATED("Use maybe version",
+                Local<Object> ToObject(Isolate* isolate) const);
+  V8_DEPRECATED("Use maybe version",
+                Local<Integer> ToInteger(Isolate* isolate) const);
+  V8_DEPRECATED("Use maybe version",
+                Local<Int32> ToInt32(Isolate* isolate) const);
 
   /**
    * Attempts to convert a string to an array index.
@@ -2518,6 +2558,9 @@ class V8_EXPORT Value : public Data {
 
   bool BooleanValue(Isolate* isolate) const;
 
+  V8_DEPRECATED("BooleanValue can never throw. Use Isolate version.",
+                V8_WARN_UNUSED_RESULT Maybe<bool> BooleanValue(
+                    Local<Context> context) const);
   V8_WARN_UNUSED_RESULT Maybe<double> NumberValue(Local<Context> context) const;
   V8_WARN_UNUSED_RESULT Maybe<int64_t> IntegerValue(
       Local<Context> context) const;
@@ -2721,10 +2764,6 @@ class V8_EXPORT String : public Name {
      */
     virtual bool IsCacheable() const { return true; }
 
-    // Disallow copying and assigning.
-    ExternalStringResourceBase(const ExternalStringResourceBase&) = delete;
-    void operator=(const ExternalStringResourceBase&) = delete;
-
    protected:
     ExternalStringResourceBase() = default;
 
@@ -2754,6 +2793,10 @@ class V8_EXPORT String : public Name {
      */
     virtual void Unlock() const {}
 
+    // Disallow copying and assigning.
+    ExternalStringResourceBase(const ExternalStringResourceBase&) = delete;
+    void operator=(const ExternalStringResourceBase&) = delete;
+
    private:
     friend class internal::ExternalString;
     friend class v8::String;
@@ -2837,23 +2880,43 @@ class V8_EXPORT String : public Name {
 
   V8_INLINE static String* Cast(v8::Value* obj);
 
+  // TODO(dcarney): remove with deprecation of New functions.
+  enum NewStringType {
+    kNormalString = static_cast<int>(v8::NewStringType::kNormal),
+    kInternalizedString = static_cast<int>(v8::NewStringType::kInternalized)
+  };
+
+  /** Allocates a new string from UTF-8 data.*/
+  static V8_DEPRECATED(
+      "Use maybe version",
+      Local<String> NewFromUtf8(Isolate* isolate, const char* data,
+                                NewStringType type = kNormalString,
+                                int length = -1));
+
   /** Allocates a new string from UTF-8 data. Only returns an empty value when
    * length > kMaxLength. **/
   static V8_WARN_UNUSED_RESULT MaybeLocal<String> NewFromUtf8(
-      Isolate* isolate, const char* data,
-      NewStringType type = NewStringType::kNormal, int length = -1);
+      Isolate* isolate, const char* data, v8::NewStringType type,
+      int length = -1);
 
   /** Allocates a new string from Latin-1 data.  Only returns an empty value
    * when length > kMaxLength. **/
   static V8_WARN_UNUSED_RESULT MaybeLocal<String> NewFromOneByte(
-      Isolate* isolate, const uint8_t* data,
-      NewStringType type = NewStringType::kNormal, int length = -1);
+      Isolate* isolate, const uint8_t* data, v8::NewStringType type,
+      int length = -1);
+
+  /** Allocates a new string from UTF-16 data.*/
+  static V8_DEPRECATED(
+      "Use maybe version",
+      Local<String> NewFromTwoByte(Isolate* isolate, const uint16_t* data,
+                                   NewStringType type = kNormalString,
+                                   int length = -1));
 
   /** Allocates a new string from UTF-16 data. Only returns an empty value when
    * length > kMaxLength. **/
   static V8_WARN_UNUSED_RESULT MaybeLocal<String> NewFromTwoByte(
-      Isolate* isolate, const uint16_t* data,
-      NewStringType type = NewStringType::kNormal, int length = -1);
+      Isolate* isolate, const uint16_t* data, v8::NewStringType type,
+      int length = -1);
 
   /**
    * Creates a new string by concatenating the left and the right strings
@@ -2892,6 +2955,10 @@ class V8_EXPORT String : public Name {
    * should the underlying buffer be deallocated or modified except through the
    * destructor of the external string resource.
    */
+  static V8_DEPRECATED(
+      "Use maybe version",
+      Local<String> NewExternal(Isolate* isolate,
+                                ExternalOneByteStringResource* resource));
   static V8_WARN_UNUSED_RESULT MaybeLocal<String> NewExternalOneByte(
       Isolate* isolate, ExternalOneByteStringResource* resource);
 
@@ -3288,8 +3355,8 @@ enum class IntegrityLevel { kFrozen, kSealed };
  */
 class V8_EXPORT Object : public Value {
  public:
-  V8_DEPRECATED("Use maybe version",
-                bool Set(Local<Value> key, Local<Value> value));
+  V8_DEPRECATE_SOON("Use maybe version",
+                    bool Set(Local<Value> key, Local<Value> value));
   /**
    * Set only return Just(true) or Empty(), so if it should never fail, use
    * result.Check().
@@ -3297,8 +3364,8 @@ class V8_EXPORT Object : public Value {
   V8_WARN_UNUSED_RESULT Maybe<bool> Set(Local<Context> context,
                                         Local<Value> key, Local<Value> value);
 
-  V8_DEPRECATED("Use maybe version",
-                bool Set(uint32_t index, Local<Value> value));
+  V8_DEPRECATE_SOON("Use maybe version",
+                    bool Set(uint32_t index, Local<Value> value));
   V8_WARN_UNUSED_RESULT Maybe<bool> Set(Local<Context> context, uint32_t index,
                                         Local<Value> value);
 
@@ -3342,11 +3409,11 @@ class V8_EXPORT Object : public Value {
   V8_WARN_UNUSED_RESULT Maybe<bool> DefineProperty(
       Local<Context> context, Local<Name> key, PropertyDescriptor& descriptor);
 
-  V8_DEPRECATED("Use maybe version", Local<Value> Get(Local<Value> key));
+  V8_DEPRECATE_SOON("Use maybe version", Local<Value> Get(Local<Value> key));
   V8_WARN_UNUSED_RESULT MaybeLocal<Value> Get(Local<Context> context,
                                               Local<Value> key);
 
-  V8_DEPRECATED("Use maybe version", Local<Value> Get(uint32_t index));
+  V8_DEPRECATE_SOON("Use maybe version", Local<Value> Get(uint32_t index));
   V8_WARN_UNUSED_RESULT MaybeLocal<Value> Get(Local<Context> context,
                                               uint32_t index);
 
@@ -3830,6 +3897,9 @@ class ReturnValue {
   }
   // Local setters
   template <typename S>
+  V8_INLINE V8_DEPRECATED("Use Global<> instead",
+                          void Set(const Persistent<S>& handle));
+  template <typename S>
   V8_INLINE void Set(const Global<S>& handle);
   template <typename S>
   V8_INLINE void Set(const TracedGlobal<S>& handle);
@@ -5217,6 +5287,38 @@ class V8_EXPORT Date : public Object {
 
   V8_INLINE static Date* Cast(Value* obj);
 
+  /**
+   * Time zone redetection indicator for
+   * DateTimeConfigurationChangeNotification.
+   *
+   * kSkip indicates V8 that the notification should not trigger redetecting
+   * host time zone. kRedetect indicates V8 that host time zone should be
+   * redetected, and used to set the default time zone.
+   *
+   * The host time zone detection may require file system access or similar
+   * operations unlikely to be available inside a sandbox. If v8 is run inside a
+   * sandbox, the host time zone has to be detected outside the sandbox before
+   * calling DateTimeConfigurationChangeNotification function.
+   */
+  enum class TimeZoneDetection { kSkip, kRedetect };
+
+  /**
+   * Notification that the embedder has changed the time zone,
+   * daylight savings time, or other date / time configuration
+   * parameters.  V8 keeps a cache of various values used for
+   * date / time computation.  This notification will reset
+   * those cached values for the current context so that date /
+   * time configuration changes would be reflected in the Date
+   * object.
+   *
+   * This API should not be called more than needed as it will
+   * negatively impact the performance of date operations.
+   */
+  V8_DEPRECATED("Use Isolate::DateTimeConfigurationChangeNotification",
+                static void DateTimeConfigurationChangeNotification(
+                    Isolate* isolate, TimeZoneDetection time_zone_detection =
+                                          TimeZoneDetection::kSkip));
+
  private:
   static void CheckCast(Value* obj);
 };
@@ -5902,6 +6004,21 @@ class V8_EXPORT FunctionTemplate : public Template {
    */
   void SetAcceptAnyReceiver(bool value);
 
+  /**
+   * Determines whether the __proto__ accessor ignores instances of
+   * the function template.  If instances of the function template are
+   * ignored, __proto__ skips all instances and instead returns the
+   * next object in the prototype chain.
+   *
+   * Call with a value of true to make the __proto__ accessor ignore
+   * instances of the function template.  Call with a value of false
+   * to make the __proto__ accessor not ignore instances of the
+   * function template.  By default, instances of a function template
+   * are not ignored.
+   */
+  V8_DEPRECATED("This feature is incompatible with ES6+.",
+                void SetHiddenPrototype(bool value));
+
   /**
    * Sets the ReadOnly flag in the attributes of the 'prototype' property
    * of functions created from this FunctionTemplate to true.
@@ -6706,12 +6823,11 @@ class V8_EXPORT MicrotaskQueue {
    */
   virtual int GetMicrotasksScopeDepth() const = 0;
 
-  MicrotaskQueue(const MicrotaskQueue&) = delete;
-  MicrotaskQueue& operator=(const MicrotaskQueue&) = delete;
-
  private:
   friend class internal::MicrotaskQueue;
   MicrotaskQueue() = default;
+  MicrotaskQueue(const MicrotaskQueue&) = delete;
+  MicrotaskQueue& operator=(const MicrotaskQueue&) = delete;
 };
 
 /**
@@ -7102,11 +7218,6 @@ enum class MemoryPressureLevel { kNone, kModerate, kCritical };
  */
 class V8_EXPORT EmbedderHeapTracer {
  public:
-  enum TraceFlags : uint64_t {
-    kNoFlags = 0,
-    kReduceMemory = 1 << 0,
-  };
-
   // Indicator for the stack state of the embedder.
   enum EmbedderStackState {
     kUnknown,
@@ -7123,24 +7234,6 @@ class V8_EXPORT EmbedderHeapTracer {
     virtual void VisitTracedGlobalHandle(const TracedGlobal<Value>& value) = 0;
   };
 
-  /**
-   * Summary of a garbage collection cycle. See |TraceEpilogue| on how the
-   * summary is reported.
-   */
-  struct TraceSummary {
-    /**
-     * Time spent managing the retained memory in milliseconds. This can e.g.
-     * include the time tracing through objects in the embedder.
-     */
-    double time = 0.0;
-
-    /**
-     * Memory retained by the embedder through the |EmbedderHeapTracer|
-     * mechanism in bytes.
-     */
-    size_t allocated_size = 0;
-  };
-
   virtual ~EmbedderHeapTracer() = default;
 
   /**
@@ -7163,8 +7256,7 @@ class V8_EXPORT EmbedderHeapTracer {
   /**
    * Called at the beginning of a GC cycle.
    */
-  V8_DEPRECATE_SOON("Use version with flags.", virtual void TracePrologue()) {}
-  virtual void TracePrologue(TraceFlags flags);
+  virtual void TracePrologue() = 0;
 
   /**
    * Called to advance tracing in the embedder.
@@ -7187,12 +7279,9 @@ class V8_EXPORT EmbedderHeapTracer {
   /**
    * Called at the end of a GC cycle.
    *
-   * Note that allocation is *not* allowed within |TraceEpilogue|. Can be
-   * overriden to fill a |TraceSummary| that is used by V8 to schedule future
-   * garbage collections.
+   * Note that allocation is *not* allowed within |TraceEpilogue|.
    */
-  virtual void TraceEpilogue() {}
-  virtual void TraceEpilogue(TraceSummary* trace_summary) { TraceEpilogue(); }
+  virtual void TraceEpilogue() = 0;
 
   /**
    * Called upon entering the final marking pause. No more incremental marking
@@ -7229,14 +7318,6 @@ class V8_EXPORT EmbedderHeapTracer {
    */
   void GarbageCollectionForTesting(EmbedderStackState stack_state);
 
-  /*
-   * Called by the embedder to signal newly allocated memory. Not bound to
-   * tracing phases. Embedders should trade off when increments are reported as
-   * V8 may consult global heuristics on whether to trigger garbage collection
-   * on this change.
-   */
-  void IncreaseAllocatedSize(size_t bytes);
-
   /*
    * Returns the v8::Isolate this tracer is attached too and |nullptr| if it
    * is not attached to any v8::Isolate.
@@ -8529,13 +8610,6 @@ class V8_EXPORT Isolate {
 
 class V8_EXPORT StartupData {
  public:
-  /**
-   * Whether the data created can be rehashed and and the hash seed can be
-   * recomputed when deserialized.
-   * Only valid for StartupData returned by SnapshotCreator::CreateBlob().
-   */
-  bool CanBeRehashed() const;
-
   const char* data;
   int raw_size;
 };
@@ -8594,10 +8668,7 @@ class V8_EXPORT V8 {
   /**
    * Sets V8 flags from a string.
    */
-  static void SetFlagsFromString(const char* str);
-  static void SetFlagsFromString(const char* str, size_t length);
-  V8_DEPRECATED("use size_t version",
-                static void SetFlagsFromString(const char* str, int length));
+  static void SetFlagsFromString(const char* str, int length);
 
   /**
    * Sets V8 flags from the command line.
@@ -8768,6 +8839,9 @@ class V8_EXPORT V8 {
                                      const char* label);
   static Value* Eternalize(Isolate* isolate, Value* handle);
 
+  static void RegisterExternallyReferencedObject(internal::Address* location,
+                                                 internal::Isolate* isolate);
+
   template <class K, class V, class T>
   friend class PersistentValueMapBase;
 
@@ -9714,6 +9788,14 @@ void Persistent<T, M>::Copy(const Persistent<S, M2>& that) {
   M::Copy(that, this);
 }
 
+template <class T>
+bool PersistentBase<T>::IsIndependent() const {
+  typedef internal::Internals I;
+  if (this->IsEmpty()) return false;
+  return I::GetNodeFlag(reinterpret_cast<internal::Address*>(this->val_),
+                        I::kNodeIsIndependentShift);
+}
+
 template <class T>
 bool PersistentBase<T>::IsWeak() const {
   typedef internal::Internals I;
@@ -9780,6 +9862,31 @@ void PersistentBase<T>::AnnotateStrongRetainer(const char* label) {
                              label);
 }
 
+template <class T>
+void PersistentBase<T>::RegisterExternalReference(Isolate* isolate) const {
+  if (IsEmpty()) return;
+  V8::RegisterExternallyReferencedObject(
+      reinterpret_cast<internal::Address*>(this->val_),
+      reinterpret_cast<internal::Isolate*>(isolate));
+}
+
+template <class T>
+void PersistentBase<T>::MarkIndependent() {
+  typedef internal::Internals I;
+  if (this->IsEmpty()) return;
+  I::UpdateNodeFlag(reinterpret_cast<internal::Address*>(this->val_), true,
+                    I::kNodeIsIndependentShift);
+}
+
+template <class T>
+void PersistentBase<T>::MarkActive() {
+  typedef internal::Internals I;
+  if (this->IsEmpty()) return;
+  I::UpdateNodeFlag(reinterpret_cast<internal::Address*>(this->val_), true,
+                    I::kNodeIsActiveShift);
+}
+
+
 template <class T>
 void PersistentBase<T>::SetWrapperClassId(uint16_t class_id) {
   typedef internal::Internals I;
@@ -9905,6 +10012,17 @@ void TracedGlobal<T>::SetFinalizationCallback(
 template <typename T>
 ReturnValue<T>::ReturnValue(internal::Address* slot) : value_(slot) {}
 
+template<typename T>
+template<typename S>
+void ReturnValue<T>::Set(const Persistent<S>& handle) {
+  TYPE_CHECK(T, S);
+  if (V8_UNLIKELY(handle.IsEmpty())) {
+    *value_ = GetDefaultValue();
+  } else {
+    *value_ = *reinterpret_cast<internal::Address*>(*handle);
+  }
+}
+
 template <typename T>
 template <typename S>
 void ReturnValue<T>::Set(const Global<S>& handle) {
@@ -10824,8 +10942,7 @@ int64_t Isolate::AdjustAmountOfExternalAllocatedMemory(
   *external_memory = amount;
 
   int64_t allocation_diff_since_last_mc =
-      static_cast<int64_t>(static_cast<uint64_t>(*external_memory) -
-                           static_cast<uint64_t>(*external_memory_at_last_mc));
+      *external_memory - *external_memory_at_last_mc;
   // Only check memory pressure and potentially trigger GC if the amount of
   // external memory increased.
   if (allocation_diff_since_last_mc > kMemoryReducerActivationLimit) {