Refactoring ImageBuffer to decouple it from Canvas2DLayerBridge

Source/core/rendering/shapes/Shape.cpp

 /*
  * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above
  *    copyright notice, this list of conditions and the following
  *    disclaimer.
@@ skipping 192 matching lines @@
 
     return shape.release();
 }
 
 PassOwnPtr<Shape> Shape::createShape(const StyleImage* styleImage, float threshold, const LayoutSize&, WritingMode writingMode, Length margin, Length padding)
 {
     ASSERT(styleImage && styleImage->isImageResource() && styleImage->cachedImage() && styleImage->cachedImage()->image());
 
     Image* image = styleImage->cachedImage()->image();
     const IntSize& imageSize = image->size();
+    OwnPtr<RasterShapeIntervals> intervals = adoptPtr(new RasterShapeIntervals(imageSize.height()));
     OwnPtr<ImageBuffer> imageBuffer = ImageBuffer::create(imageSize);
-
-    OwnPtr<RasterShapeIntervals> intervals = adoptPtr(new RasterShapeIntervals(imageSize.height()));
-
     if (imageBuffer) {
         GraphicsContext* graphicsContext = imageBuffer->context();
         graphicsContext->drawImage(image, IntPoint());
 
         RefPtr<Uint8ClampedArray> pixelArray = imageBuffer->getUnmultipliedImageData(IntRect(IntPoint(), imageSize));
         unsigned pixelArrayLength = pixelArray->length();
         unsigned pixelArrayOffset = 3; // Each pixel is four bytes: RGBA.
         uint8_t alphaPixelThreshold = threshold * 255;
 
         ASSERT(static_cast<unsigned>(imageSize.width() * imageSize.height() * 4) == pixelArrayLength);
@@ skipping 26 matching lines @@
 
     OwnPtr<Shape> shape = createRectangleShape(bounds, radii);
     shape->m_writingMode = writingMode;
     shape->m_margin = floatValueForLength(margin, 0);
     shape->m_padding = floatValueForLength(padding, 0);
 
     return shape.release();
 }
 
 } // namespace WebCore