stop using SkXfermode -- use SkBlendMode instead

cc/layers/layer.h

Index: cc/layers/layer.h
diff --git a/cc/layers/layer.h b/cc/layers/layer.h
index 5e460cbd4717cb1e93445139865918be6409d1bc..751546ed7895e891117edde46293d5d9f06a395e 100644
--- a/cc/layers/layer.h
+++ b/cc/layers/layer.h
@@ -32,7 +32,6 @@
 #include "cc/trees/target_property.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkPicture.h"
-#include "third_party/skia/include/core/SkXfermode.h"
 #include "ui/gfx/geometry/point3_f.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/rect_f.h"
@@ -140,16 +139,16 @@ class CC_EXPORT Layer : public base::RefCounted<Layer> {
 
   virtual bool AlwaysUseActiveTreeOpacity() const;
 
-  void SetBlendMode(SkXfermode::Mode blend_mode);
-  SkXfermode::Mode blend_mode() const { return inputs_.blend_mode; }
+  void SetBlendMode(SkBlendMode blend_mode);
+  SkBlendMode blend_mode() const { return inputs_.blend_mode; }
 
-  void set_draw_blend_mode(SkXfermode::Mode blend_mode) {
+  void set_draw_blend_mode(SkBlendMode blend_mode) {
     if (draw_blend_mode_ == blend_mode)
       return;
     draw_blend_mode_ = blend_mode;
     SetNeedsPushProperties();
   }
-  SkXfermode::Mode draw_blend_mode() const { return draw_blend_mode_; }
+  SkBlendMode draw_blend_mode() const { return draw_blend_mode_; }
 
   // A layer is root for an isolated group when it and all its descendants are
   // drawn over a black and fully transparent background, creating an isolated
@@ -598,7 +597,7 @@ class CC_EXPORT Layer : public base::RefCounted<Layer> {
     scoped_refptr<Layer> mask_layer;
 
     float opacity;
-    SkXfermode::Mode blend_mode;
+    SkBlendMode blend_mode;
 
     bool is_root_for_isolated_group : 1;
 
@@ -692,7 +691,7 @@ class CC_EXPORT Layer : public base::RefCounted<Layer> {
   SkColor safe_opaque_background_color_;
   // draw_blend_mode may be different than blend_mode_,
   // when a RenderSurface re-parents the layer's blend_mode.
-  SkXfermode::Mode draw_blend_mode_;
+  SkBlendMode draw_blend_mode_;
   std::unique_ptr<std::set<Layer*>> scroll_children_;
 
   std::unique_ptr<std::set<Layer*>> clip_children_;