Oilpan: move 2D Canvas and WebGL objects to the heap.

Source/core/html/canvas/WebGLSharedWebGraphicsContext3D.h

Index: Source/core/html/canvas/WebGLSharedWebGraphicsContext3D.h
diff --git a/Source/core/html/canvas/WebGLSharedWebGraphicsContext3D.h b/Source/core/html/canvas/WebGLSharedWebGraphicsContext3D.h
new file mode 100644
index 0000000000000000000000000000000000000000..6ecb1dba53c6798ccb6e39d6b6f38aa4c7c4d19d
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+++ b/Source/core/html/canvas/WebGLSharedWebGraphicsContext3D.h
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+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef WebGLSharedWebGraphicsContext3D_h
+#define WebGLSharedWebGraphicsContext3D_h
+
+#include "wtf/Forward.h"
+#include "wtf/RefCounted.h"
+#include "wtf/RefPtr.h"
+
+namespace blink {
+
+class WebGraphicsContext3D;
+class DrawingBuffer;
+
+#if ENABLE(OILPAN)
+// The attached WebGLContextObjects are finalized using the
+// blink::WebGraphicsContext3D object of this object's DrawingBuffer.
+// Naturally the DrawingBuffer must then be kept alive until those
+// finalizers have run. With Oilpan, accomplish that by having the
+// WebGLContextObjects keep a RefPtr<> to an off-heap object that
+// safely handles the eventual release of the underlying
+// DrawingBuffer.
+class WebGLSharedWebGraphicsContext3D FINAL : public RefCounted<WebGLSharedWebGraphicsContext3D> {
+public:
+    static PassRefPtr<WebGLSharedWebGraphicsContext3D> create(PassRefPtr<DrawingBuffer>);
+
+    ~WebGLSharedWebGraphicsContext3D();
+
+    // Disposing and updating the underlying DrawingBuffer;
+    // needed when handling loss and restoration of graphics contexts.
+    void dispose();
+    void update(PassRefPtr<DrawingBuffer>);
+
+    DrawingBuffer* drawingBuffer() const;
+
+    blink::WebGraphicsContext3D* webContext() const;
+private:
+    explicit WebGLSharedWebGraphicsContext3D(PassRefPtr<DrawingBuffer>);
+
+    RefPtr<DrawingBuffer> m_buffer;
+};
+#endif
+
+}
+
+#endif // WebGLSharedWebGraphicsContext3D_h