stop using SkXfermode -- use SkBlendMode instead

cc/layers/render_surface_impl.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_LAYERS_RENDER_SURFACE_IMPL_H_
 #define CC_LAYERS_RENDER_SURFACE_IMPL_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 35 matching lines @@
 
   // Returns the rect that encloses the RenderSurfaceImpl including any
   // reflection.
   gfx::RectF DrawableContentRect() const;
 
   void SetDrawOpacity(float opacity) {
     draw_properties_.draw_opacity = opacity;
   }
   float draw_opacity() const { return draw_properties_.draw_opacity; }
 
-  SkXfermode::Mode BlendMode() const;
+  SkBlendMode BlendMode() const;
   bool UsesDefaultBlendMode() const;
 
   void SetNearestOcclusionImmuneAncestor(const RenderSurfaceImpl* surface) {
     nearest_occlusion_immune_ancestor_ = surface;
   }
   const RenderSurfaceImpl* nearest_occlusion_immune_ancestor() const {
     return nearest_occlusion_immune_ancestor_;
   }
 
   SkColor GetDebugBorderColor() const;
@@ skipping 147 matching lines @@
   int target_render_surface_layer_index_history_;
   size_t current_layer_index_history_;
 
   friend class LayerIterator;
 
   DISALLOW_COPY_AND_ASSIGN(RenderSurfaceImpl);
 };
 
 }  // namespace cc
 #endif  // CC_LAYERS_RENDER_SURFACE_IMPL_H_