CSS Background Blending doesn't work for svg layers.

Source/core/svg/graphics/SVGImage.cpp

 /*
  * Copyright (C) 2006 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. 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 172 matching lines @@
     drawForContainer(buffer->context(), containerSize, zoom, imageBufferSize, zoomedContainerRect, CompositeSourceOver, BlendModeNormal);
     RefPtr<Image> image = buffer->copyImage(DontCopyBackingStore, Unscaled);
 
     // Adjust the source rect and transform due to the image buffer's scaling.
     FloatRect scaledSrcRect = srcRect;
     scaledSrcRect.scale(imageBufferScale.width(), imageBufferScale.height());
 
     image->drawPattern(context, scaledSrcRect, scaleWithoutCTM, phase, compositeOp, dstRect);
 }
 
-void SVGImage::draw(GraphicsContext* context, const FloatRect& dstRect, const FloatRect& srcRect, CompositeOperator compositeOp, BlendMode)
+void SVGImage::draw(GraphicsContext* context, const FloatRect& dstRect, const FloatRect& srcRect, CompositeOperator compositeOp, BlendMode blendMode)
 {
     if (!m_page)
         return;
 
     FrameView* view = frameView();
 
     GraphicsContextStateSaver stateSaver(*context);
-    context->setCompositeOperation(compositeOp);
+    context->setCompositeOperation(compositeOp, blendMode);
     context->clip(enclosingIntRect(dstRect));
     if (compositeOp != CompositeSourceOver)
         context->beginTransparencyLayer(1);
 
     FloatSize scale(dstRect.width() / srcRect.width(), dstRect.height() / srcRect.height());
 
     // We can only draw the entire frame, clipped to the rect we want. So compute where the top left
     // of the image would be if we were drawing without clipping, and translate accordingly.
     FloatSize topLeftOffset(srcRect.location().x() * scale.width(), srcRect.location().y() * scale.height());
     FloatPoint destOffset = dstRect.location() - topLeftOffset;
@@ skipping 162 matching lines @@
 void SVGImage::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
 {
     MemoryClassInfo info(memoryObjectInfo, this, WebCoreMemoryTypes::CachedResourceImage);
     Image::reportMemoryUsage(memoryObjectInfo);
     info.addMember(m_chromeClient, "chromeClient");
     info.addMember(m_page, "page");
 }
 
 }