stop using SkXfermode -- use SkBlendMode instead

cc/layers/render_surface_impl.cc

Index: cc/layers/render_surface_impl.cc
diff --git a/cc/layers/render_surface_impl.cc b/cc/layers/render_surface_impl.cc
index 483ad01162f162a3b3410542126dc763746e5528..b16fcfe4a298a14e65f197760b4b710cb8cd363b 100644
--- a/cc/layers/render_surface_impl.cc
+++ b/cc/layers/render_surface_impl.cc
@@ -104,12 +104,12 @@ gfx::RectF RenderSurfaceImpl::DrawableContentRect() const {
   return drawable_content_rect;
 }
 
-SkXfermode::Mode RenderSurfaceImpl::BlendMode() const {
+SkBlendMode RenderSurfaceImpl::BlendMode() const {
   return OwningEffectNode()->blend_mode;
 }
 
 bool RenderSurfaceImpl::UsesDefaultBlendMode() const {
-  return BlendMode() == SkXfermode::kSrcOver_Mode;
+  return BlendMode() == SkBlendMode::kSrcOver;
 }
 
 SkColor RenderSurfaceImpl::GetDebugBorderColor() const {