cc: Move filters to the effect tree

cc/trees/property_tree_builder.cc

Index: cc/trees/property_tree_builder.cc
diff --git a/cc/trees/property_tree_builder.cc b/cc/trees/property_tree_builder.cc
index 6d9c2f20c70effbfdc49a256683c9e7e55980cfb..a16033d71ab8341242dae60ad7f9d43364ee21db 100644
--- a/cc/trees/property_tree_builder.cc
+++ b/cc/trees/property_tree_builder.cc
@@ -767,6 +767,14 @@ static inline float Opacity(LayerImpl* layer) {
   return layer->test_properties()->opacity;
 }
 
+static inline const FilterOperations& Filters(Layer* layer) {
+  return layer->filters();
+}
+
+static inline const FilterOperations& Filters(LayerImpl* layer) {
+  return layer->test_properties()->filters;
+}
+
 static inline const FilterOperations& BackgroundFilters(Layer* layer) {
   return layer->background_filters();
 }
@@ -822,7 +830,7 @@ bool ShouldCreateRenderSurface(LayerType* layer,
   }
 
   // If the layer uses a CSS filter.
-  if (!layer->filters().IsEmpty() || !BackgroundFilters(layer).IsEmpty()) {
+  if (!Filters(layer).IsEmpty() || !BackgroundFilters(layer).IsEmpty()) {
     return true;
   }
 
@@ -928,15 +936,17 @@ bool AddEffectNodeIfNeeded(
   const bool has_transparency = EffectiveOpacity(layer) != 1.f;
   const bool has_potential_opacity_animation =
       HasPotentialOpacityAnimation(layer);
+  const bool has_potential_filter_animation =
+      HasPotentiallyRunningFilterAnimation(layer);
   const bool should_create_render_surface = ShouldCreateRenderSurface(
       layer, data_from_ancestor.compound_transform_since_render_target,
       data_from_ancestor.axis_align_since_render_target);
   data_for_children->axis_align_since_render_target &=
       AnimationsPreserveAxisAlignment(layer);
 
-  bool requires_node = is_root || has_transparency ||
-                       has_potential_opacity_animation ||
-                       should_create_render_surface;
+  bool requires_node =
+      is_root || has_transparency || has_potential_opacity_animation ||
+      has_potential_filter_animation || should_create_render_surface;

[jaydasika, 2016/07/20 20:53:06]

Is this condition required ? Doesn't has_potential_filter_animation =>
should_create_render_surface ?

[ajuma, 2016/07/21 16:42:18]

Done. (It's surprising that has_potential_opacity_animation doesn't also imply
should_create_render_surface.)

[jaydasika, 2016/07/21 17:22:35]

It sounds like a bug to me. For the case, current opacity is 1 and opacity is
animating we are not creating a render surface. I think we should. WDYT ?

[ajuma, 2016/07/21 18:49:41]

Yeah, it's a bug. I'll fix it in a separate CL.

It turns out that Blink happens to avoid hitting this bug since during opacity
animations, it changes opacity 1 to 1 - \epsilon. See
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/animation...
and
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/css/resol...

 
   int parent_id = data_from_ancestor.effect_tree_parent;
 
@@ -958,11 +968,14 @@ bool AddEffectNodeIfNeeded(
   node.opacity = Opacity(layer);
   node.has_render_surface = should_create_render_surface;
   node.has_copy_request = HasCopyRequest(layer);
+  node.filters = Filters(layer);

[weiliangc, 2016/07/21 01:06:38]

This would make a copy of the Filter owned by Layer/LayerImpl's test properties.
Would explicitly changing ownership be better? To avoid the case of changing
filter on layers when only using filters on effect node?

[ajuma, 2016/07/21 16:42:18]

If we transfer ownership rather than copying, we'll get stuck the next time we
need to rebuild property trees, since the old property trees (owning the filter)
will be gone, and the layer will no longer have a copy either.

   node.background_filters = BackgroundFilters(layer);
   node.has_potential_opacity_animation = has_potential_opacity_animation;
+  node.has_potential_filter_animation = has_potential_filter_animation;
   node.double_sided = DoubleSided(layer);
   node.subtree_hidden = HideLayerAndSubtree(layer);
   node.is_currently_animating_opacity = OpacityIsAnimating(layer);
+  node.is_currently_animating_filter = FilterIsAnimating(layer);
 
   EffectTree& effect_tree = data_for_children->property_trees->effect_tree;
   if (MaskLayer(layer)) {