Moving GraphicsContext and dependencies from core to platform.

Source/core/platform/graphics/Canvas2DLayerManager.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
-    notice, this list of conditions and the following disclaimer in the
-    documentation and/or other materials provided with the distribution.
-
-THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
-EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
-DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
-LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
-ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(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 Canvas2DLayerManager_h
-#define Canvas2DLayerManager_h
-
-#include "core/platform/graphics/Canvas2DLayerBridge.h"
-#include "public/platform/WebThread.h"
-
-class Canvas2DLayerManagerTest;
-
-namespace WebCore {
-
-class Canvas2DLayerManager : public blink::WebThread::TaskObserver {
-public:
-    static Canvas2DLayerManager& get();
-    void init(size_t maxBytesAllocated, size_t targetBytesAllocated);
-    virtual ~Canvas2DLayerManager();
-
-    void layerAllocatedStorageChanged(Canvas2DLayerBridge*, intptr_t deltaBytes);
-    void layerDidDraw(Canvas2DLayerBridge*);
-    void layerToBeDestroyed(Canvas2DLayerBridge*);
-private:
-    Canvas2DLayerManager();
-
-    // internal methods
-    void freeMemoryIfNecessary();
-    bool isInList(Canvas2DLayerBridge*);
-    void addLayerToList(Canvas2DLayerBridge*);
-    void removeLayerFromList(Canvas2DLayerBridge*);
-    virtual void willProcessTask() OVERRIDE;
-    virtual void didProcessTask() OVERRIDE;
-
-    size_t m_bytesAllocated;
-    size_t m_maxBytesAllocated;
-    size_t m_targetBytesAllocated;
-    bool m_taskObserverActive;
-    DoublyLinkedList<Canvas2DLayerBridge> m_layerList;
-
-    friend class ::Canvas2DLayerManagerTest; // for unit testing
-};
-
-}
-
-#endif
-