Use newImageSnapshot() to get an image from a Canvas

Source/platform/graphics/ImageBufferSurface.h

Index: Source/platform/graphics/ImageBufferSurface.h
diff --git a/Source/platform/graphics/ImageBufferSurface.h b/Source/platform/graphics/ImageBufferSurface.h
index 5bc193712dc16f7d10acadfc8b7ec889ae9cd4b4..647d90427cd09b40b3e1dbac16002a0addcfd414 100644
--- a/Source/platform/graphics/ImageBufferSurface.h
+++ b/Source/platform/graphics/ImageBufferSurface.h
@@ -40,6 +40,7 @@
 
 class SkBitmap;
 class SkCanvas;
+class SkImage;
 class SkPicture;
 
 namespace blink { class WebLayer; }
@@ -56,7 +57,7 @@ enum OpacityMode {
 class PLATFORM_EXPORT ImageBufferSurface {
     WTF_MAKE_NONCOPYABLE(ImageBufferSurface); WTF_MAKE_FAST_ALLOCATED;
 public:
-    virtual ~ImageBufferSurface() { }
+    virtual ~ImageBufferSurface();
 
     virtual SkCanvas* canvas() const = 0;
     virtual const SkBitmap& bitmap();
@@ -76,6 +77,8 @@ public:
     virtual PassRefPtr<SkPicture> getPicture();
     virtual void didClearCanvas() { }
 
+    virtual PassRefPtr<SkImage> newImageSnapshot() const;
+
     OpacityMode opacityMode() const { return m_opacityMode; }
     const IntSize& size() const { return m_size; }
     void notifyIsValidChanged(bool isValid) const;