Add support for converting cc::FilterOperations into an SkImageFilter

cc/trees/layer_tree_host_common.cc

 // Copyright 2011 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/layer_tree_host_common.h"
 
 #include <algorithm>
 
 #include "base/debug/trace_event.h"
 #include "cc/base/math_util.h"
@@ skipping 537 matching lines @@
     return true;
   }
 
   // If the layer has a reflection.
   if (layer->replica_layer()) {
     DCHECK(!is_root);
     return true;
   }
 
   // If the layer uses a CSS filter.
-  if (!layer->filters().IsEmpty() || !layer->background_filters().IsEmpty() ||
-      layer->filter()) {
+  if (!layer->filters().IsEmpty() || !layer->background_filters().IsEmpty()) {
     DCHECK(!is_root);
     return true;
   }
 
   int num_descendants_that_draw_content =
       layer->draw_properties().num_descendants_that_draw_content;
 
   // If the layer flattens its subtree (i.e. the layer doesn't preserve-3d), but
   // it is treated as a 3D object by its parent (i.e. parent does preserve-3d).
   if (LayerIsInExisting3DRenderingContext(layer) && !layer->preserves_3d() &&
@@ skipping 971 matching lines @@
       DrawProperties<LayerType, RenderSurfaceType>&
       replica_mask_draw_properties =
           layer->replica_layer()->mask_layer()->draw_properties();
       replica_mask_draw_properties.render_target = layer;
       replica_mask_draw_properties.visible_content_rect =
           gfx::Rect(layer->content_bounds());
     }
 
     // TODO(senorblanco): make this smarter for the SkImageFilter case (check
     // for pixel-moving filters)
-    if (layer->filters().HasFilterThatMovesPixels() || layer->filter())
+    if (layer->filters().HasReferenceFilter() ||

[Stephen White, 2013/09/11 17:56:25]

It occurs to me that HasFilterThatMovesPixels() should probably return true
(conservatively) when it has a reference filter. Then we could just call that,
and skip the HasReferenceFilter() call here. Could be done in a followup.

That'll make it easier to clean this up once SkImageFilter gets the smarts.

[danakj, 2013/09/11 18:01:16]

That's true, but elsewhere we check that and then use the outsets to tell how
far they moved. And with a reference filter those outsets are wrong. So I'd
prefer to keep it a dcheck as is.

[Stephen White, 2013/09/11 18:04:19]

Ahh, ok. In that case, ignore me.

+        layer->filters().HasFilterThatMovesPixels())
       nearest_ancestor_surface_that_moves_pixels = render_surface;
 
     render_surface->SetNearestAncestorThatMovesPixels(
         nearest_ancestor_surface_that_moves_pixels);
 
     layer_or_ancestor_clips_descendants = false;
     bool subtree_is_clipped_by_surface_bounds = false;
     if (ancestor_clips_subtree) {
       // It may be the layer or the surface doing the clipping of the subtree,
       // but in either case, we'll be clipping to the projected clip rect of our
@@ skipping 654 matching lines @@
   // At this point, we think the point does hit the touch event handler region
   // on the layer, but we need to walk up the parents to ensure that the layer
   // was not clipped in such a way that the hit point actually should not hit
   // the layer.
   if (PointIsClippedBySurfaceOrClipRect(screen_space_point, layer_impl))
     return false;
 
   return true;
 }
 }  // namespace cc