Reland: Make 2D canvas disable gpu acceleration when getImageData is called

third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h

 /*
  * Copyright (C) 2012 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:
  *
  * 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
@@ skipping 95 matching lines @@
     bool isAccelerated() const;
     void setFilterQuality(SkFilterQuality);
     void setIsHidden(bool);
     void setImageBuffer(ImageBuffer*);
     void didDraw(const FloatRect&);
     bool writePixels(const SkImageInfo&, const void* pixels, size_t rowBytes, int x, int y);
     void flush();
     void flushGpu();
     void prepareSurfaceForPaintingIfNeeded();
     bool isHidden() { return m_isHidden; }
+    OpacityMode opacityMode() { return m_opacityMode; }
 
     void beginDestruction();
     void hibernate();
     bool isHibernating() const { return m_hibernationImage.get(); }
 
     PassRefPtr<SkImage> newImageSnapshot(AccelerationHint, SnapshotReason);
 
     // The values of the enum entries must not change because they are used for
     // usage metrics histograms. New values can be added to the end.
     enum HibernationEvent {
@@ skipping 60 matching lines @@
     };
 
     Canvas2DLayerBridge(std::unique_ptr<WebGraphicsContext3DProvider>, const IntSize&, int msaaSampleCount, OpacityMode, AccelerationMode);
     gpu::gles2::GLES2Interface* contextGL();
     void startRecording();
     void skipQueuedDrawCommands();
     void flushRecordingOnly();
     void unregisterTaskObserver();
     void reportSurfaceCreationFailure();
 
+    void disableAcceleration();
+
     // WebThread::TaskOberver implementation
     void willProcessTask() override;
     void didProcessTask() override;
 
     SkSurface* getOrCreateSurface(AccelerationHint = PreferAcceleration);
     bool shouldAccelerate(AccelerationHint) const;
 
     // Returns the GL filter associated with |m_filterQuality|.
     GLenum getGLFilter();
 
@@ skipping 44 matching lines @@
     SkFilterQuality m_filterQuality;
     bool m_isHidden;
     bool m_isDeferralEnabled;
     bool m_isRegisteredTaskObserver;
     bool m_renderingTaskCompletedForCurrentFrame;
     bool m_softwareRenderingWhileHidden;
     bool m_surfaceCreationFailedAtLeastOnce = false;
     bool m_hibernationScheduled = false;
 
     friend class Canvas2DLayerBridgeTest;
+    friend class CanvasRenderingContext2DTest;
 
     uint32_t m_lastImageId;
 
     enum {
         // We should normally not have more that two active mailboxes at a time,
         // but sometime we may have three due to the async nature of mailbox handling.
         MaxActiveMailboxes = 3,
     };
 
     Deque<MailboxInfo, MaxActiveMailboxes> m_mailboxes;
     GLenum m_lastFilter;
     AccelerationMode m_accelerationMode;
     OpacityMode m_opacityMode;
     const IntSize m_size;
     int m_recordingPixelCount;
 
 #if USE_IOSURFACE_FOR_2D_CANVAS
     // Each element in this vector represents an IOSurface backed texture that
     // is ready to be reused.
     // Elements in this vector can safely be purged in low memory conditions.
     Vector<ImageInfo> m_imageInfoCache;
 #endif // USE_IOSURFACE_FOR_2D_CANVAS
 };
 
 } // namespace blink
 
 #endif