Accurate transfer of SerializedScriptValue allocation costs.

third_party/WebKit/Source/bindings/core/v8/SerializedScriptValue.h

 /*
  * Copyright (C) 2009, 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 118 matching lines @@
       const ImageBitmapArray&,
       ExceptionState&);
 
   // Informs V8 about external memory allocated and owned by this object.
   // Large values should contribute to GC counters to eventually trigger a GC,
   // otherwise flood of postMessage() can cause OOM.
   // Ok to invoke multiple times (only adds memory once).
   // The memory registration is revoked automatically in destructor.
   void registerMemoryAllocatedWithCurrentScriptContext();
 
-  // Upon passing a serialized value from one context to another (via a
-  // postMessage()), the allocation amounts it has registered with the
-  // 'origining' context must be discharged, as the 'target' context will assume
-  // ownership of value. This method takes care of the first part of the
-  // external allocation bookkeeping, the above registration method the other
-  // half.
-  void unregisterMemoryAllocatedByCurrentScriptContext();
+  // The dual, unregistering / subtracting the external memory allocation costs
+  // of this SerializedScriptValue with the current context. This includes
+  // discounting the cost of the transferables.
+  //
+  // The value is updated and marked as having no allocations registered,
+  // hence subsequent calls will be no-ops.
+  void unregisterMemoryAllocatedWithCurrentScriptContext();
 
   const uint8_t* data() const { return m_dataBuffer.get(); }
   size_t dataLengthInBytes() const { return m_dataBufferSize; }
 
   BlobDataHandleMap& blobDataHandles() { return m_blobDataHandles; }
   ArrayBufferContentsArray* getArrayBufferContentsArray() {
     return m_arrayBufferContentsArray.get();
   }
   ImageBitmapContentsArray* getImageBitmapContentsArray() {
     return m_imageBitmapContentsArray.get();
@@ skipping 25 matching lines @@
   void transferOffscreenCanvas(v8::Isolate*,
                                const OffscreenCanvasArray&,
                                ExceptionState&);
 
   DataBufferPtr m_dataBuffer;
   size_t m_dataBufferSize = 0;
 
   std::unique_ptr<ArrayBufferContentsArray> m_arrayBufferContentsArray;
   std::unique_ptr<ImageBitmapContentsArray> m_imageBitmapContentsArray;
   BlobDataHandleMap m_blobDataHandles;
-  size_t m_externallyAllocatedMemory;
-  bool m_adjustTransferableExternalAllocationOnContextTransfer;
+
+  bool m_hasRegisteredExternalAllocation;
+  bool m_transferablesNeedExternalAllocationRegistration;
 };
 
 template <>
 struct NativeValueTraits<SerializedScriptValue>
     : public NativeValueTraitsBase<SerializedScriptValue> {
   CORE_EXPORT static inline PassRefPtr<SerializedScriptValue> nativeValue(
       v8::Isolate* isolate,
       v8::Local<v8::Value> value,
       ExceptionState& exceptionState) {
     return SerializedScriptValue::serialize(isolate, value, nullptr, nullptr,
                                             exceptionState);
   }
 };
 
 }  // namespace blink
 
 #endif  // SerializedScriptValue_h