Add support for converting cc::FilterOperations into an SkImageFilter

cc/trees/occlusion_tracker.cc

 // Copyright 2012 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.
 
 #include "cc/trees/occlusion_tracker.h"
 
 #include <algorithm>
 
 #include "cc/base/math_util.h"
 #include "cc/debug/overdraw_metrics.h"
@@ skipping 222 matching lines @@
 
   // If the occlusion within the surface can not be applied to things outside of
   // the surface's subtree, then clear the occlusion here so it won't be used.
   // TODO(senorblanco):  Make this smarter for SkImageFilter case:  once
   // SkImageFilters can report affectsOpacity(), call that.
   if (finished_target->mask_layer() ||
       !SurfaceOpacityKnown(surface) ||
       surface->draw_opacity() < 1 ||
       target_is_only_for_copy_request ||
       finished_target->filters().HasFilterThatAffectsOpacity() ||
-      finished_target->filter()) {
+      finished_target->filters().HasReferenceFilter()) {

[danakj, 2013/09/09 22:04:50]

can't this just be removed?

[ajuma, 2013/09/10 21:17:58]

Yes, removed this and moved the TODO from above to
FilterOperations::HasFilterThatAffectsOpacity.

     stack_.back().occlusion_from_outside_target.Clear();
     stack_.back().occlusion_from_inside_target.Clear();
   } else if (!SurfaceTransformsToTargetKnown(surface)) {
     stack_.back().occlusion_from_inside_target.Clear();
     stack_.back().occlusion_from_outside_target.Clear();
   }
 }
 
 template <typename LayerType>
 static void ReduceOcclusionBelowSurface(LayerType* contributing_layer,
@@ skipping 483 matching lines @@
   }
 
   return unoccluded_rect;
 }
 
 // Instantiate (and export) templates here for the linker.
 template class OcclusionTrackerBase<Layer, RenderSurface>;
 template class OcclusionTrackerBase<LayerImpl, RenderSurfaceImpl>;
 
 }  // namespace cc