Use SkImage as a backing store for copying 2d Contexts to ImageBitmaps.

Source/core/platform/graphics/SkiaImage.h

Index: Source/core/platform/graphics/SkiaImage.h
diff --git a/Source/core/platform/graphics/SkiaImage.h b/Source/core/platform/graphics/SkiaImage.h
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index 0000000000000000000000000000000000000000..9599743e48cc4409f5095cd127221be445b8f563
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+++ b/Source/core/platform/graphics/SkiaImage.h
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+/*
+ * Copyright (C) 2013 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:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * 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.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
+ * OWNER OR 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 SkiaImage_h
+#define SkiaImage_h
+
+#include "core/platform/graphics/Image.h"
+#include "core/platform/graphics/IntSize.h"
+#include "wtf/Forward.h"
+
+class SkImage;
+
+namespace WebCore {
+
+class GraphicsContext;
+
+class SkiaImage : public Image {

[Justin Novosad, 2013/07/22 15:35:41]

Let's give this a blinky name. How about ReadOnlyBitmapImage?

+
+public:
+    static PassRefPtr<SkiaImage> create(SkImage* image, ImageObserver* observer = 0)
+    {
+        return adoptRef(new SkiaImage(image, observer));
+    }
+
+    virtual IntSize size() const { return m_size; }
+
+private:

[Justin Novosad, 2013/07/22 15:35:41]

You should overload all the virtual methods of Image that are not compatible
with the read-only semantic of SkImage and make them call ASSERT_NOT_REACHED()
with a comment that says that the call is not supported.

+    SkiaImage(SkImage*, ImageObserver* = 0);
+
+    virtual void draw(GraphicsContext*, const FloatRect&, const FloatRect&, CompositeOperator, BlendMode) OVERRIDE;
+    virtual void draw(GraphicsContext*, const FloatRect&, const FloatRect&, CompositeOperator, BlendMode, RespectImageOrientationEnum) OVERRIDE;
+
+    IntSize m_size;
+    SkImage* m_image;
+};
+
+} // namespace WebCore
+
+#endif // SkiaImage_h