Make beginLayer() and CanvasRenderingContext2D use SkXfermode::Mode.

Source/platform/graphics/GraphicsContext.cpp

 /*
  * Copyright (C) 2003, 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2013 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:
  * 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
@@ skipping 420 matching lines @@
     paint->setLCDRenderText(couldUseLCDRenderedText());
 }
 
 bool GraphicsContext::couldUseLCDRenderedText() const
 {
     if (RuntimeEnabledFeatures::slimmingPaintEnabled())
         return true;
     return m_isCertainlyOpaque && m_shouldSmoothFonts;
 }
 
+void GraphicsContext::setCompositeOperation(SkXfermode::Mode xferMode)
+{
+    if (contextDisabled())
+        return;
+    mutableState()->setCompositeOperation(xferMode);
+}
+
 void GraphicsContext::setCompositeOperation(CompositeOperator compositeOperation, WebBlendMode blendMode)
 {
-    if (contextDisabled())
-        return;
-    mutableState()->setCompositeOperation(compositeOperation, blendMode);
+    SkXfermode::Mode xferMode = WebCoreCompositeToSkiaComposite(compositeOperation, blendMode);
+    setCompositeOperation(xferMode);
+}
+
+CompositeOperator GraphicsContext::compositeOperation() const
+{
+    return compositeOperatorFromSkia(immutableState()->compositeOperation());
+}
+
+WebBlendMode GraphicsContext::blendModeOperation() const
+{
+    return blendModeFromSkia(immutableState()->compositeOperation());
 }
 
 SkColorFilter* GraphicsContext::colorFilter() const
 {
     return immutableState()->colorFilter();
 }
 
 void GraphicsContext::setColorFilter(ColorFilter colorFilter)
 {
     GraphicsContextState* stateToSet = mutableState();
@@ skipping 31 matching lines @@
     if (matrix.isIdentity())
         return;
 
     ASSERT(m_canvas);
 
     m_canvas->concat(matrix);
 }
 
 void GraphicsContext::beginTransparencyLayer(float opacity, const FloatRect* bounds)
 {
-    beginLayer(opacity, immutableState()->compositeOperator(), bounds);
+    beginLayer(opacity, immutableState()->compositeOperation(), bounds);
 }
 
-void GraphicsContext::beginLayer(float opacity, CompositeOperator op, const FloatRect* bounds, ColorFilter colorFilter, ImageFilter* imageFilter)
+void GraphicsContext::beginLayer(float opacity, SkXfermode::Mode xfermode, const FloatRect* bounds, ColorFilter colorFilter, ImageFilter* imageFilter)
 {
     if (contextDisabled())
         return;
 
     SkPaint layerPaint;
     layerPaint.setAlpha(static_cast<unsigned char>(opacity * 255));
-    layerPaint.setXfermodeMode(WebCoreCompositeToSkiaComposite(op, m_paintState->blendMode()));
+    layerPaint.setXfermodeMode(xfermode);
     layerPaint.setColorFilter(WebCoreColorFilterToSkiaColorFilter(colorFilter).get());
     layerPaint.setImageFilter(imageFilter);
 
     if (bounds) {
         SkRect skBounds = WebCoreFloatRectToSKRect(*bounds);
         saveLayer(&skBounds, &layerPaint);
     } else {
         saveLayer(0, &layerPaint);
     }
 
@@ skipping 1484 matching lines @@
         // being returned from computeInterpolationQuality.
         resampling = InterpolationLow;
     }
     resampling = limitInterpolationQuality(this, resampling);
     paint->setFilterLevel(static_cast<SkPaint::FilterLevel>(resampling));
 
     return initialSaveCount;
 }
 
 } // namespace blink