Add support for converting cc::FilterOperations into an SkImageFilter

cc/layers/layer_impl.h

Index: cc/layers/layer_impl.h
diff --git a/cc/layers/layer_impl.h b/cc/layers/layer_impl.h
index 484de955761d719a43af81eb65a0600b72a1ab55..017e59fb7690dfad1ac5902c4665db733e417ed0 100644
--- a/cc/layers/layer_impl.h
+++ b/cc/layers/layer_impl.h
@@ -193,9 +193,6 @@ class CC_EXPORT LayerImpl : LayerAnimationValueObserver {
     return background_filters_;
   }
 
-  void SetFilter(const skia::RefPtr<SkImageFilter>& filter);
-  skia::RefPtr<SkImageFilter> filter() const { return filter_; }
-
   void SetMasksToBounds(bool masks_to_bounds);
   bool masks_to_bounds() const { return masks_to_bounds_; }
 
@@ -599,7 +596,6 @@ class CC_EXPORT LayerImpl : LayerAnimationValueObserver {
 
   FilterOperations filters_;
   FilterOperations background_filters_;
-  skia::RefPtr<SkImageFilter> filter_;
 
  protected:
   DrawMode current_draw_mode_;