Fixing Canvas2DLayerBridge to handle lost graphics contexts

Source/core/platform/graphics/chromium/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 19 matching lines @@
 #include "SkImage.h"
 #include "core/platform/graphics/GraphicsContext3D.h"
 #include "core/platform/graphics/IntSize.h"
 #include <public/WebExternalTextureLayer.h>
 #include <public/WebExternalTextureLayerClient.h>
 #include <public/WebExternalTextureMailbox.h>
 #include <wtf/DoublyLinkedList.h>
 #include <wtf/PassOwnPtr.h>
 #include <wtf/RefPtr.h>
 
+class Canvas2DLayerBridgeTest;
+
 namespace WebKit {
 class WebGraphicsContext3D;
 }
 
 namespace WebCore {
 
 class Canvas2DLayerBridge : public WebKit::WebExternalTextureLayerClient, public SkDeferredCanvas::NotificationClient, public DoublyLinkedListNode<Canvas2DLayerBridge> {
     WTF_MAKE_NONCOPYABLE(Canvas2DLayerBridge);
 public:
     enum OpacityMode {
         Opaque,
         NonOpaque
     };
 
     enum ThreadMode {
         SingleThread,
         Threaded
     };
 
-    static PassOwnPtr<Canvas2DLayerBridge> create(PassRefPtr<GraphicsContext3D> context, SkDeferredCanvas* canvas, OpacityMode opacityMode, ThreadMode threading)
-    {
-        return adoptPtr(new Canvas2DLayerBridge(context, canvas, opacityMode, threading));
-    }
+    static PassOwnPtr<Canvas2DLayerBridge> create(PassRefPtr<GraphicsContext3D>, const IntSize&, OpacityMode, ThreadMode);
 
     virtual ~Canvas2DLayerBridge();
 
     // WebKit::WebExternalTextureLayerClient implementation.
     virtual unsigned prepareTexture(WebKit::WebTextureUpdater&) OVERRIDE;
     virtual WebKit::WebGraphicsContext3D* context() OVERRIDE;
     virtual bool prepareMailbox(WebKit::WebExternalTextureMailbox*) OVERRIDE;
     virtual void mailboxReleased(const WebKit::WebExternalTextureMailbox&) OVERRIDE;
 
     // SkDeferredCanvas::NotificationClient implementation
     virtual void prepareForDraw() OVERRIDE;
     virtual void storageAllocatedForRecordingChanged(size_t) OVERRIDE;
     virtual void flushedDrawCommands() OVERRIDE;
     virtual void skippedPendingDrawCommands() OVERRIDE;
 
     // Methods used by Canvas2DLayerManager
     virtual size_t freeMemoryIfPossible(size_t); // virtual for mocking
     virtual void flush(); // virtual for mocking
     virtual size_t storageAllocatedForRecording(); // virtual for faking
     size_t bytesAllocated() const {return m_bytesAllocated;}
     void limitPendingFrames();
 
     WebKit::WebLayer* layer();
     void contextAcquired();
+    SkCanvas* getCanvas() {return m_canvas;}

[Stephen White, 2013/05/31 15:06:18]

Nit: Missing spaces?

 
     unsigned backBufferTexture();
 
+    bool isValid();
+
 protected:
-    Canvas2DLayerBridge(PassRefPtr<GraphicsContext3D>, SkDeferredCanvas*, OpacityMode, ThreadMode);
+    virtual PassRefPtr<GraphicsContext3D> getSharedContext() const; // virtual for faking
+    Canvas2DLayerBridge(PassRefPtr<GraphicsContext3D>, SkDeferredCanvas*);
+    void init(OpacityMode, ThreadMode);
 
     SkDeferredCanvas* m_canvas;
     OwnPtr<WebKit::WebExternalTextureLayer> m_layer;
     RefPtr<GraphicsContext3D> m_context;
     size_t m_bytesAllocated;
     bool m_didRecordDrawCommand;
     int m_framesPending;
 
+    friend class ::Canvas2DLayerBridgeTest; // for unit testing
+
     friend class WTF::DoublyLinkedListNode<Canvas2DLayerBridge>;
     Canvas2DLayerBridge* m_next;
     Canvas2DLayerBridge* m_prev;
 
 #if ENABLE(CANVAS_USES_MAILBOX)
     enum MailboxStatus {
         MailboxInUse,
         MailboxReleased,
         MailboxAvailable,
     };
 
     struct MailboxInfo {
         WebKit::WebExternalTextureMailbox m_mailbox;
         SkAutoTUnref<SkImage> m_image;
         MailboxStatus m_status;
 
         MailboxInfo(const MailboxInfo&);
         MailboxInfo() {}
     };
     MailboxInfo* createMailboxInfo();
 
     uint32_t m_lastImageId;
     Vector<MailboxInfo> m_mailboxes;
 #endif
 };
 
 }
 
 #endif