Remove mask painting.

sky/engine/core/rendering/RenderLayer.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 271 matching lines @@
     // paintLayerContents() assumes that the caller will clip to the bounds of the painting dirty rect if necessary.
     void paintLayerContents(GraphicsContext*, const LayerPaintingInfo&, PaintLayerFlags);
 
     void paintLayerByApplyingTransform(GraphicsContext*, const LayerPaintingInfo&, PaintLayerFlags, const LayoutPoint& translationOffset = LayoutPoint());
 
     void paintChildren(unsigned childrenToVisit, GraphicsContext*, const LayerPaintingInfo&, PaintLayerFlags);
 
     void paintForeground(GraphicsContext*, GraphicsContext* transparencyLayerContext,
         const LayoutRect& transparencyPaintDirtyRect, bool haveTransparency, const LayerPaintingInfo&,
         LayoutPoint& layerLocation, ClipRect& layerForegroundRect);
-    void paintMask(GraphicsContext*, const LayerPaintingInfo&,
-        LayoutPoint& layerLocation, ClipRect& layerBackgroundRect);
 
     RenderLayer* hitTestLayer(RenderLayer* rootLayer, RenderLayer* containerLayer, const HitTestRequest& request, HitTestResult& result,
                               const LayoutRect& hitTestRect, const HitTestLocation&, bool appliedTransform,
                               const HitTestingTransformState* transformState = 0, double* zOffset = 0);
     RenderLayer* hitTestLayerByApplyingTransform(RenderLayer* rootLayer, RenderLayer* containerLayer, const HitTestRequest&, HitTestResult&,
         const LayoutRect& hitTestRect, const HitTestLocation&, const HitTestingTransformState* = 0, double* zOffset = 0,
         const LayoutPoint& translationOffset = LayoutPoint());
     RenderLayer* hitTestChildren(ChildrenIteration, RenderLayer* rootLayer, const HitTestRequest&, HitTestResult&,
                              const LayoutRect& hitTestRect, const HitTestLocation&,
                              const HitTestingTransformState* transformState, double* zOffsetForDescendants, double* zOffset,
@@ skipping 69 matching lines @@
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showLayerTree(const blink::RenderLayer*);
 void showLayerTree(const blink::RenderObject*);
 #endif
 
 #endif  // SKY_ENGINE_CORE_RENDERING_RENDERLAYER_H_