Fix background blending for some cases where it did not work at all. The fix adds the blendMode par…

Source/core/platform/graphics/CrossfadeGeneratedImage.cpp

 /*
  * Copyright (C) 2011 Apple Inc. 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 62 matching lines @@
     if (m_crossfadeSize != toImageSize)
         context->scale(FloatSize(static_cast<float>(m_crossfadeSize.width()) / toImageSize.width(),
                                  static_cast<float>(m_crossfadeSize.height()) / toImageSize.height()));
     context->setAlpha(m_percentage);
     context->drawImage(m_toImage, IntPoint(), CompositePlusLighter);
     context->restore();
 
     context->endTransparencyLayer();
 }
 
-void CrossfadeGeneratedImage::draw(GraphicsContext* context, const FloatRect& dstRect, const FloatRect& srcRect, CompositeOperator compositeOp, BlendMode)
+void CrossfadeGeneratedImage::draw(GraphicsContext* context, const FloatRect& dstRect, const FloatRect& srcRect, CompositeOperator compositeOp, BlendMode blendMode)
 {
     GraphicsContextStateSaver stateSaver(*context);
-    context->setCompositeOperation(compositeOp);
+    context->setCompositeOperation(compositeOp, blendMode);
     context->clip(dstRect);
     context->translate(dstRect.x(), dstRect.y());
     if (dstRect.size() != srcRect.size())
         context->scale(FloatSize(dstRect.width() / srcRect.width(), dstRect.height() / srcRect.height()));
     context->translate(-srcRect.x(), -srcRect.y());
 
     drawCrossfade(context);
 }
 
-void CrossfadeGeneratedImage::drawPattern(GraphicsContext* context, const FloatRect& srcRect, const FloatSize& scale, const FloatPoint& phase, CompositeOperator compositeOp, const FloatRect& dstRect, BlendMode)
+void CrossfadeGeneratedImage::drawPattern(GraphicsContext* context, const FloatRect& srcRect, const FloatSize& scale, const FloatPoint& phase, CompositeOperator compositeOp, const FloatRect& dstRect, BlendMode blendMode)
 {
     OwnPtr<ImageBuffer> imageBuffer = ImageBuffer::create(m_size, 1, context->isAccelerated() ? Accelerated : Unaccelerated);
     if (!imageBuffer)
         return;
 
     // Fill with the cross-faded image.
     GraphicsContext* graphicsContext = imageBuffer->context();
     drawCrossfade(graphicsContext);
 
     // Tile the image buffer into the context.
-    imageBuffer->drawPattern(context, srcRect, scale, phase, compositeOp, dstRect);
+    imageBuffer->drawPattern(context, srcRect, scale, phase, compositeOp, dstRect, blendMode);
 }
 
 }