WIP: Adjust externally allocated memory when ImageBitmap is transferred

third_party/WebKit/Source/platform/graphics/UnacceleratedStaticBitmapImage.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/graphics/UnacceleratedStaticBitmapImage.h"
 
 #include "third_party/skia/include/core/SkImage.h"
+#include "v8/include/v8.h"
 
 namespace blink {
 
 PassRefPtr<UnacceleratedStaticBitmapImage>
 UnacceleratedStaticBitmapImage::create(sk_sp<SkImage> image) {
   return adoptRef(new UnacceleratedStaticBitmapImage(std::move(image)));
 }
 
 UnacceleratedStaticBitmapImage::UnacceleratedStaticBitmapImage(
     sk_sp<SkImage> image)
@@ skipping 18 matching lines @@
                                           RespectImageOrientationEnum,
                                           ImageClampingMode clampMode) {
   StaticBitmapImage::drawHelper(canvas, flags, dstRect, srcRect, clampMode,
                                 m_image);
 }
 
 sk_sp<SkImage> UnacceleratedStaticBitmapImage::imageForCurrentFrame() {
   return m_image;
 }
 
+void UnacceleratedStaticBitmapImage::
+    registerExternalAllocationWithCurrentContext() {
+  if (!m_image)
+    return;
+  int externallyAllocatedMemory = m_image->width() * m_image->height() * 4;

[jbroman, 2017/04/04 15:44:56]

probably not your problem, but beware overflow in this calculation

+  v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(
+      static_cast<int64_t>(externallyAllocatedMemory));
+}
+
+void UnacceleratedStaticBitmapImage::
+    unregisterExternalAllocationWithCurrentContext() {
+  if (!m_image)
+    return;
+  int externallyAllocatedMemory = m_image->width() * m_image->height() * 4;
+  v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(
+      -static_cast<int64_t>(externallyAllocatedMemory));
+}
+
 }  // namespace blink