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 19 matching lines @@
 #include "config.h"
 #include "core/rendering/shapes/Shape.h"
 
 #include "core/fetch/ImageResource.h"
 #include "core/platform/graphics/ImageBuffer.h"
 #include "core/rendering/shapes/PolygonShape.h"
 #include "core/rendering/shapes/RasterShape.h"
 #include "core/rendering/shapes/RectangleShape.h"
 #include "platform/LengthFunctions.h"
 #include "platform/geometry/FloatSize.h"
+#include "platform/graphics/UnacceleratedImageBufferSurface.h"
 #include "platform/graphics/WindRule.h"
 #include "wtf/MathExtras.h"
 #include "wtf/OwnPtr.h"
 
 namespace WebCore {
 
 static PassOwnPtr<Shape> createRectangleShape(const FloatRect& bounds, const FloatSize& radii)
 {
     ASSERT(bounds.width() >= 0 && bounds.height() >= 0 && radii.width() >= 0 && radii.height() >= 0);
     return adoptPtr(new RectangleShape(bounds, radii));
@@ skipping 153 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<ImageBuffer> imageBuffer = ImageBuffer::create(imageSize);
-
     OwnPtr<RasterShapeIntervals> intervals = adoptPtr(new RasterShapeIntervals(imageSize.height()));
-
-    if (imageBuffer) {
-        GraphicsContext* graphicsContext = imageBuffer->context();
+    OwnPtr<ImageBufferSurface> surface = adoptPtr(new UnacceleratedImageBufferSurface(imageSize));
+    if (surface->isValid()) {
+        ImageBuffer imageBuffer(surface.release());
+        GraphicsContext* graphicsContext = imageBuffer.context();
         graphicsContext->drawImage(image, IntPoint());
 
-        RefPtr<Uint8ClampedArray> pixelArray = imageBuffer->getUnmultipliedImageData(IntRect(IntPoint(), imageSize));
+        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);
 
         for (int y = 0; y < imageSize.height(); ++y) {
             int startX = -1;
             for (int x = 0; x < imageSize.width() && pixelArrayOffset < pixelArrayLength; ++x, pixelArrayOffset += 4) {
                 uint8_t alpha = pixelArray->item(pixelArrayOffset);
                 if ((startX == -1) && alpha > alphaPixelThreshold) {
                     startX = x;
                 } else if (startX != -1 && (alpha <= alphaPixelThreshold || x == imageSize.width() - 1)) {
                     intervals->appendInterval(y, startX, x);
                     startX = -1;
                 }
             }
         }
     }
 
     OwnPtr<RasterShape> rasterShape = adoptPtr(new RasterShape(intervals.release(), imageSize));
     rasterShape->m_writingMode = writingMode;
     rasterShape->m_margin = floatValueForLength(margin, 0);
     rasterShape->m_padding = floatValueForLength(padding, 0);
     return rasterShape.release();
 }
 
 } // namespace WebCore