Add canvas blending modes under a runtime flag

Source/WebCore/platform/graphics/skia/ImageSkia.cpp

 /*
  * Copyright (c) 2008, Google 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:
  * 
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 599 matching lines @@
         m_isSolidColor = true;
         m_solidColor = Color(frame->bitmap().getColor(0, 0));
     }
 }
 
 void BitmapImage::draw(GraphicsContext* ctxt, const FloatRect& dstRect, const FloatRect& srcRect, ColorSpace colorSpace, CompositeOperator compositeOp, BlendMode blendMode)
 {
     draw(ctxt, dstRect, srcRect, colorSpace, compositeOp, blendMode, DoNotRespectImageOrientation);
 }
 
-void BitmapImage::draw(GraphicsContext* ctxt, const FloatRect& dstRect, const FloatRect& srcRect, ColorSpace colorSpace, CompositeOperator compositeOp, BlendMode, RespectImageOrientationEnum shouldRespectImageOrientation)
+void BitmapImage::draw(GraphicsContext* ctxt, const FloatRect& dstRect, const FloatRect& srcRect, ColorSpace colorSpace, CompositeOperator compositeOp, BlendMode blendMode, RespectImageOrientationEnum shouldRespectImageOrientation)
 {
     // Spin the animation to the correct frame before we try to draw it, so we
     // don't draw an old frame and then immediately need to draw a newer one,
     // causing flicker and wasting CPU.
     startAnimation();
 
     RefPtr<NativeImageSkia> bm = nativeImageForCurrentFrame();
     if (!bm)
         return; // It's too early and we don't have an image yet.
 
@@ skipping 22 matching lines @@
             // The destination rect will have it's width and height already reversed for the orientation of
             // the image, as it was needed for page layout, so we need to reverse it back here.
             normDstRect = FloatRect(normDstRect.x(), normDstRect.y(), normDstRect.height(), normDstRect.width());
         }
     }
 
     paintSkBitmap(ctxt->platformContext(),
         *bm,
         normSrcRect,
         normDstRect,
-        WebCoreCompositeToSkiaComposite(compositeOp));
+        WebCoreCompositeToSkiaComposite(compositeOp, blendMode));
 
     if (ImageObserver* observer = imageObserver())
         observer->didDraw(this);
 }
 
 } // namespace WebCore