Lose/restore WebGL contexts if multisampling blackist status changes at runtime.

Source/core/html/canvas/WebGLRenderingContext.h

 /*
  * Copyright (C) 2009 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 11 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
  */
 
 #ifndef WebGLRenderingContext_h
 #define WebGLRenderingContext_h
 
 #include "core/dom/ActiveDOMObject.h"
 #include "core/html/canvas/CanvasRenderingContext.h"
 #include "core/html/canvas/WebGLGetInfo.h"
+#include "core/page/Page.h"
 #include "core/platform/Timer.h"
 #include "core/platform/graphics/GraphicsContext3D.h"
 #include "core/platform/graphics/ImageBuffer.h"
 
 #include <wtf/Float32Array.h>
 #include <wtf/Int32Array.h>
 #include <wtf/OwnArrayPtr.h>
 #include <wtf/text/WTFString.h>
 #include <wtf/Uint8Array.h>
 
@@ skipping 245 matching lines @@
                              GC3Dsizei stride, long long offset, ExceptionCode&);
 
     void viewport(GC3Dint x, GC3Dint y, GC3Dsizei width, GC3Dsizei height);
 
     // WEBKIT_lose_context support
     enum LostContextMode {
         // Lost context occurred at the graphics system level.
         RealLostContext,
 
         // Lost context provoked by WEBKIT_lose_context.
-        SyntheticLostContext
+        SyntheticLostContext,
+
+        // A synthetic lost context that should attempt to recover automatically
+        AutoRecoverSyntheticLostContext
     };
     void forceLostContext(LostContextMode);
     void forceRestoreContext();
     void loseContextImpl(LostContextMode);
 
     GraphicsContext3D* graphicsContext3D() const { return m_context.get(); }
     WebGLContextGroup* contextGroup() const { return m_contextGroup.get(); }
     virtual PlatformLayer* platformLayer() const;
 
     void reshape(int width, int height);
@@ skipping 16 matching lines @@
     friend class WebGLFramebuffer;
     friend class WebGLObject;
     friend class OESVertexArrayObject;
     friend class WebGLDebugShaders;
     friend class WebGLCompressedTextureATC;
     friend class WebGLCompressedTexturePVRTC;
     friend class WebGLCompressedTextureS3TC;
     friend class WebGLRenderingContextErrorMessageCallback;
     friend class WebGLVertexArrayObjectOES;
 
-    WebGLRenderingContext(HTMLCanvasElement*, PassRefPtr<GraphicsContext3D>, GraphicsContext3D::Attributes);
+    WebGLRenderingContext(HTMLCanvasElement*, PassRefPtr<GraphicsContext3D>, GraphicsContext3D::Attributes, GraphicsContext3D::Attributes);
     void initializeNewContext();
     void setupFlags();
 
     void addSharedObject(WebGLSharedObject*);
     void addContextObject(WebGLContextObject*);
     void detachAndRemoveAllObjects();
 
     void destroyGraphicsContext3D();
     void markContextChanged();
 
@@ skipping 141 matching lines @@
     bool m_drawBuffersSupported;
 
     GC3Dint m_packAlignment;
     GC3Dint m_unpackAlignment;
     bool m_unpackFlipY;
     bool m_unpackPremultiplyAlpha;
     GC3Denum m_unpackColorspaceConversion;
     bool m_contextLost;
     LostContextMode m_contextLostMode;
     GraphicsContext3D::Attributes m_attributes;
+    GraphicsContext3D::Attributes m_requestedAttributes;
 
     bool m_layerCleared;
     GC3Dfloat m_clearColor[4];
     bool m_scissorEnabled;
     GC3Dfloat m_clearDepth;
     GC3Dint m_clearStencil;
     GC3Dboolean m_colorMask[4];
     GC3Dboolean m_depthMask;
 
     bool m_stencilEnabled;
@@ skipping 256 matching lines @@
     // First time called, if EXT_draw_buffers is supported, query the value; otherwise return 0.
     // Later, return the cached value.
     GC3Dint getMaxDrawBuffers();
     GC3Dint getMaxColorAttachments();
 
     void setBackDrawBuffer(GC3Denum);
 
     void restoreCurrentFramebuffer();
     void restoreCurrentTexture2D();
 
+    class WebGLSettingsChangedObserver : public Page::SettingsChangedObserver, public RefCounted<WebGLSettingsChangedObserver> {
+    public:
+        WebGLSettingsChangedObserver(WebGLRenderingContext*, Page*);
+        virtual void settingsChanged(Settings*);
+        virtual ~WebGLSettingsChangedObserver();
+
+    private:
+        WebGLRenderingContext* m_context;
+        Page* m_page;

[abarth-chromium, 2013/05/06 21:58:30]

This object is RefCounted but it holds raw pointers to these objects...  How are
the lifetimes of this object and these pointers related?

+        bool m_multisamplingAllowed;
+    };
+
+    RefPtr<WebGLSettingsChangedObserver> m_settingsChangedObserver;
+
     friend class WebGLStateRestorer;
     friend class WebGLRenderingContextEvictionManager;
 
     static Vector<WebGLRenderingContext*>& activeContexts();
     static Vector<WebGLRenderingContext*>& forciblyEvictedContexts();
 
     static void activateContext(WebGLRenderingContext*);
     static void deactivateContext(WebGLRenderingContext*, bool addToInactiveList);
     static void willDestroyContext(WebGLRenderingContext*);
     static void forciblyLoseOldestContext(const String& reason);
     static IntSize oldestContextSize();
 };
 
 } // namespace WebCore
 
 #endif