Initial implementation of display list backed 2D canvases

Source/platform/graphics/ImageBuffer.cpp

Index: Source/platform/graphics/ImageBuffer.cpp
diff --git a/Source/platform/graphics/ImageBuffer.cpp b/Source/platform/graphics/ImageBuffer.cpp
index f5eb85e735415ef9707a1b6dc70e5144a855bb3e..35f25d397e7153317557edd336693bf90b4978e2 100644
--- a/Source/platform/graphics/ImageBuffer.cpp
+++ b/Source/platform/graphics/ImageBuffer.cpp
@@ -52,6 +52,7 @@
 #include "public/platform/WebExternalTextureMailbox.h"
 #include "public/platform/WebGraphicsContext3D.h"
 #include "public/platform/WebGraphicsContext3DProvider.h"
+#include "third_party/skia/include/core/SkPicture.h"
 #include "third_party/skia/include/effects/SkTableColorFilter.h"
 #include "wtf/MathExtras.h"
 #include "wtf/text/Base64.h"
@@ -80,12 +81,12 @@ ImageBuffer::ImageBuffer(PassOwnPtr<ImageBufferSurface> surface)
     : m_surface(surface)
     , m_client(0)
 {
-    m_surface->setImageBuffer(this);
     if (m_surface->canvas()) {
         m_context = adoptPtr(new GraphicsContext(m_surface->canvas()));
         m_context->setCertainlyOpaque(m_surface->opacityMode() == Opaque);
         m_context->setAccelerated(m_surface->isAccelerated());
     }
+    m_surface->setImageBuffer(this);
 }
 
 ImageBuffer::~ImageBuffer()
@@ -236,6 +237,12 @@ void ImageBuffer::draw(GraphicsContext* context, const FloatRect& destRect, cons
         return;
 
     FloatRect srcRect = srcPtr ? *srcPtr : FloatRect(FloatPoint(), size());
+    RefPtr<SkPicture> picture = m_surface->getPicture();
+    if (picture) {
+        context->drawPicture(picture.release(), destRect, srcRect, op, blink::WebBlendModeNormal);
+        return;
+    }
+
     SkBitmap bitmap = m_surface->bitmap();
     // For ImageBufferSurface that enables cachedBitmap, Use the cached Bitmap for CPU side usage
     // if it is available, otherwise generate and use it.