Implementation of 2D canvas context lost/restored events

Source/platform/graphics/ImageBuffer.h

 /*
  * Copyright (C) 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. 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.
@@ skipping 37 matching lines @@
 class SkCanvas;
 
 namespace blink {
 class WebGraphicsContext3D;
 }
 
 namespace WebCore {
 
 class DrawingBuffer;
 class Image;
+class ImageBufferClient;
 class IntPoint;
 class IntRect;
 
 enum Multiply {
     Premultiplied,
     Unmultiplied
 };
 
 enum BackingStoreCopy {
     CopyBackingStore, // Guarantee subsequent draws don't affect the copy.
     DontCopyBackingStore // Subsequent draws may affect the copy.
 };
 
 enum ScaleBehavior {
     Scaled,
     Unscaled
 };
 
 class PLATFORM_EXPORT ImageBuffer {
     WTF_MAKE_NONCOPYABLE(ImageBuffer); WTF_MAKE_FAST_ALLOCATED;
 public:
     static PassOwnPtr<ImageBuffer> create(const IntSize&, OpacityMode = NonOpaque);
     static PassOwnPtr<ImageBuffer> create(PassOwnPtr<ImageBufferSurface>);
 
     ~ImageBuffer();
 
+    void setClient(ImageBufferClient* client) { m_client = client; }
+
     const IntSize& size() const { return m_surface->size(); }
     bool isAccelerated() const { return m_surface->isAccelerated(); }
+    bool isSurfaceValid() const;
+    bool restoreSurface() const;
 
     void setIsHidden(bool hidden) { m_surface->setIsHidden(hidden); }
 
     GraphicsContext* context() const;
 
     const SkBitmap& bitmap() const;
 
     PassRefPtr<Image> copyImage(BackingStoreCopy = CopyBackingStore, ScaleBehavior = Scaled) const;
     // Give hints on the faster copyImage Mode, return DontCopyBackingStore if it supports the DontCopyBackingStore behavior
     // or return CopyBackingStore if it doesn't.
@@ skipping 14 matching lines @@
     // Extensions3D::canUseCopyTextureCHROMIUM().
     // Destroys the TEXTURE_2D binding for the active texture unit of the passed context
     bool copyToPlatformTexture(blink::WebGraphicsContext3D*, Platform3DObject, GLenum, GLenum, GLint, bool, bool);
 
     Platform3DObject getBackingTexture();
 
     bool copyRenderingResultsFromDrawingBuffer(DrawingBuffer*);
 
     void flush();
 
+    void notifySurfaceInvalid();
+
 private:
     ImageBuffer(PassOwnPtr<ImageBufferSurface>);
-    bool isValid() const;
 
     void draw(GraphicsContext*, const FloatRect&, const FloatRect& = FloatRect(0, 0, -1, -1), CompositeOperator = CompositeSourceOver, blink::WebBlendMode = blink::WebBlendModeNormal);
     void drawPattern(GraphicsContext*, const FloatRect&, const FloatSize&, const FloatPoint&, CompositeOperator, const FloatRect&, blink::WebBlendMode, const IntSize& repeatSpacing = IntSize());
     static PassRefPtr<SkColorFilter> createColorSpaceFilter(ColorSpace srcColorSpace, ColorSpace dstColorSpace);
 
     friend class GraphicsContext;
     friend class GeneratedImage;
     friend class CrossfadeGeneratedImage;
     friend class GradientGeneratedImage;
     friend class SkiaImageFilterBuilder;
 
     OwnPtr<ImageBufferSurface> m_surface;
     OwnPtr<GraphicsContext> m_context;
+    ImageBufferClient* m_client;
 };
 
 struct ImageDataBuffer {
     ImageDataBuffer(const IntSize& size, PassRefPtr<Uint8ClampedArray> data) : m_size(size), m_data(data) { }
     IntSize size() const { return m_size; }
     unsigned char* data() const { return m_data->data(); }
 
     IntSize m_size;
     RefPtr<Uint8ClampedArray> m_data;
 };
 
 String PLATFORM_EXPORT ImageDataToDataURL(const ImageDataBuffer&, const String& mimeType, const double* quality);
 
 } // namespace WebCore
 
 #endif // ImageBuffer_h