Cancel GPU acceleration for 2D canvas when drawing very large images

third_party/WebKit/Source/core/html/HTMLVideoElement.h

 /*
  * Copyright (C) 2007, 2008, 2009, 2010 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 69 matching lines @@
 
     // CanvasImageSource implementation
     PassRefPtr<Image> getSourceImageForCanvas(SourceImageStatus*, AccelerationHint, SnapshotReason, const FloatSize&) const override;
     bool isVideoElement() const override { return true; }
     bool wouldTaintOrigin(SecurityOrigin*) const override;
     FloatSize elementSize(const FloatSize&) const override;
     const KURL& sourceURL() const override { return currentSrc(); }
     bool isHTMLVideoElement() const override { return true; }
     int sourceWidth() override { return videoWidth(); }
     int sourceHeight() override { return videoHeight(); }
+    bool isAccelerated() const override { return false; } // Video elements currently always go through RAM when used as a canvas image source.
 
     // ImageBitmapSource implementation
     IntSize bitmapSourceSize() const override;
     ScriptPromise createImageBitmap(ScriptState*, EventTarget&, Optional<IntRect> cropRect, const ImageBitmapOptions&, ExceptionState&) override;
 
 private:
     HTMLVideoElement(Document&);
 
     bool layoutObjectIsNeeded(const ComputedStyle&) override;
     LayoutObject* createLayoutObject(const ComputedStyle&) override;
     void attachLayoutTree(const AttachContext& = AttachContext()) override;
     void parseAttribute(const QualifiedName&, const AtomicString&, const AtomicString&) override;
     bool isPresentationAttribute(const QualifiedName&) const override;
     void collectStyleForPresentationAttribute(const QualifiedName&, const AtomicString&, MutableStylePropertySet*) override;
     bool isURLAttribute(const Attribute&) const override;
     const AtomicString imageSourceURL() const override;
 
     void updateDisplayState() override;
     void didMoveToNewDocument(Document& oldDocument) override;
     void setDisplayMode(DisplayMode) override;
 
     Member<HTMLImageLoader> m_imageLoader;
 
     AtomicString m_defaultPosterURL;
 };
 
 } // namespace blink
 
 #endif // HTMLVideoElement_h