Implementation of 2D canvas context lost/restored events

Source/core/html/canvas/CanvasRenderingContext2D.h

 /*
  * Copyright (C) 2006, 2007, 2009, 2010, 2011, 2012 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 94 matching lines @@
 
     float shadowBlur() const;
     void setShadowBlur(float);
 
     String shadowColor() const;
     void setShadowColor(const String&);
 
     float globalAlpha() const;
     void setGlobalAlpha(float);
 
+    bool isContextLost() const;
+
     String globalCompositeOperation() const;
     void setGlobalCompositeOperation(const String&);
 
     void save() { ++m_stateStack.last().m_unrealizedSaveCount; }
     void restore();
 
     PassRefPtr<SVGMatrixTearOff> currentTransform() const
     {
         return SVGMatrixTearOff::create(state().m_transform);
     }
@@ skipping 101 matching lines @@
     LineJoin getLineJoin() const { return state().m_lineJoin; }
 
     bool imageSmoothingEnabled() const;
     void setImageSmoothingEnabled(bool);
 
     PassRefPtr<Canvas2DContextAttributes> getContextAttributes() const;
 
     void drawFocusIfNeeded(Element*);
     bool drawCustomFocusRing(Element*);
 
+    void loseContext();
+    void restoreContext();
+
 private:
     struct State FINAL : CSSFontSelectorClient {
         State();
         virtual ~State();
 
         State(const State&);
         State& operator=(const State&);
 
         // CSSFontSelectorClient implementation
         virtual void fontsNeedUpdate(CSSFontSelector*) OVERRIDE;
@@ skipping 32 matching lines @@
     CanvasRenderingContext2D(HTMLCanvasElement*, const Canvas2DContextAttributes* attrs, bool usesCSSCompatibilityParseMode);
 
     State& modifiableState() { ASSERT(!state().m_unrealizedSaveCount); return m_stateStack.last(); }
     const State& state() const { return m_stateStack.last(); }
 
     void applyLineDash() const;
     void setShadow(const FloatSize& offset, float blur, RGBA32 color);
     void applyShadow();
     bool shouldDrawShadows() const;
 
+    void dispatchContextLostEvent(Timer<CanvasRenderingContext2D>*);
+    void dispatchContextRestoredEvent(Timer<CanvasRenderingContext2D>*);
+    void tryRestoreSurfaceEvent(Timer<CanvasRenderingContext2D>*);

[Stephen White, 2014/03/25 23:25:04]

Naming nit: does "surface" really have a meaning at this level?

+
     bool computeDirtyRect(const FloatRect& localBounds, FloatRect*);
     bool computeDirtyRect(const FloatRect& localBounds, const FloatRect& transformedClipBounds, FloatRect*);
     void didDraw(const FloatRect&);
 
     GraphicsContext* drawingContext() const;
 
     void unwindStateStack();
     void realizeSaves();
 
     void applyStrokePattern();
@@ skipping 30 matching lines @@
     virtual bool isAccelerated() const OVERRIDE;
     virtual bool hasAlpha() const OVERRIDE { return m_hasAlpha; }
 
     virtual bool isTransformInvertible() const OVERRIDE { return state().m_invertibleCTM; }
 
     virtual blink::WebLayer* platformLayer() const OVERRIDE;
 
     Vector<State, 1> m_stateStack;
     bool m_usesCSSCompatibilityParseMode;
     bool m_hasAlpha;
+    bool m_isContextLost;
+    bool m_contextRestorable;
+    Canvas2DContextStorage m_storageMode;
     MutableStylePropertyMap m_fetchedFonts;
+    unsigned m_tryRestoreSurfaceAttemptCount;
+    Timer<CanvasRenderingContext2D> m_dispatchContextLostEventTimer;
+    Timer<CanvasRenderingContext2D> m_dispatchContextRestoredEventTimer;
+    Timer<CanvasRenderingContext2D> m_tryRestoreSurfaceEventTimer;
 };
 
 DEFINE_TYPE_CASTS(CanvasRenderingContext2D, CanvasRenderingContext, context, context->is2d(), context.is2d());
 
 } // namespace WebCore
 
 #endif