Add support for converting cc::FilterOperations into an SkImageFilter

cc/layers/delegated_renderer_layer_impl_unittest.cc

Index: cc/layers/delegated_renderer_layer_impl_unittest.cc
diff --git a/cc/layers/delegated_renderer_layer_impl_unittest.cc b/cc/layers/delegated_renderer_layer_impl_unittest.cc
index a641e00eaf0f047bbe077193f6d190626788cf84..0ab0de3abbde226c7288f67c320b96e18a823d93 100644
--- a/cc/layers/delegated_renderer_layer_impl_unittest.cc
+++ b/cc/layers/delegated_renderer_layer_impl_unittest.cc
@@ -549,7 +549,6 @@ class DelegatedRendererLayerImplTestTransform
         child_pass_rect,  // contents_changed_since_last_frame
         gfx::RectF(),  // mask_uv_rect
         FilterOperations(),  // filters
-        skia::RefPtr<SkImageFilter>(),  // filter
         FilterOperations());  // background_filters
     quad_sink.Append(render_pass_quad.PassAs<DrawQuad>(), &data);
 
@@ -951,7 +950,6 @@ class DelegatedRendererLayerImplTestClip
         child_pass_rect,  // contents_changed_since_last_frame
         gfx::RectF(),  // mask_uv_rect
         FilterOperations(),  // filters
-        skia::RefPtr<SkImageFilter>(),  // filter
         FilterOperations());  // background_filters
     quad_sink.Append(render_pass_quad.PassAs<DrawQuad>(), &data);