Make CanvasRenderingContext2D use SkCanvas directly

Source/core/html/HTMLCanvasElement.cpp

Index: Source/core/html/HTMLCanvasElement.cpp
diff --git a/Source/core/html/HTMLCanvasElement.cpp b/Source/core/html/HTMLCanvasElement.cpp
index 37db4a2cc4859f46d9449032234d3c8571f886e3..09bc5d57aaba75922dfa80f5b3462ef1ea602a2a 100644
--- a/Source/core/html/HTMLCanvasElement.cpp
+++ b/Source/core/html/HTMLCanvasElement.cpp
@@ -700,7 +700,7 @@ void HTMLCanvasElement::updateExternallyAllocatedMemory() const
 
 GraphicsContext* HTMLCanvasElement::drawingContext() const
 {
-    return buffer() ? m_imageBuffer->context() : 0;
+    return buffer() ? m_imageBuffer->context() : nullptr;
 }
 
 GraphicsContext* HTMLCanvasElement::existingDrawingContext() const
@@ -711,6 +711,19 @@ GraphicsContext* HTMLCanvasElement::existingDrawingContext() const
     return drawingContext();
 }
 
+SkCanvas* HTMLCanvasElement::drawingCanvas() const
+{
+    return buffer() ? m_imageBuffer->canvas() : nullptr;
+}
+
+SkCanvas* HTMLCanvasElement::existingDrawingCanvas() const
+{
+    if (!hasImageBuffer())
+        return nullptr;
+
+    return m_imageBuffer->canvas();
+}
+
 ImageBuffer* HTMLCanvasElement::buffer() const
 {
     ASSERT(m_context);