cc : Create effect nodes for non axis aligned clips

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 7853b0112b26755ef0fb16dbc1063d07a975f78c..ab44f929880710a697d4e8069b4ab93364487d9e 100644
--- a/cc/trees/property_tree_builder.cc
+++ b/cc/trees/property_tree_builder.cc
@@ -56,6 +56,7 @@ struct DataForRecursion {
   const gfx::Transform* device_transform;
   gfx::Transform compound_transform_since_render_target;
   bool axis_align_since_render_target;
+  bool not_axis_aligned_since_last_clip;
   SkColor safe_opaque_background_color;
 };
 
@@ -891,8 +892,19 @@ bool AddEffectNodeIfNeeded(
   data_for_children->axis_align_since_render_target &=
       AnimationsPreserveAxisAlignment(layer);
 
+  bool not_axis_aligned_since_last_clip =
+      data_from_ancestor.not_axis_aligned_since_last_clip
+          ? true
+          : !AnimationsPreserveAxisAlignment(layer) ||
+                !Transform(layer).Preserves2dAxisAlignment();

[chrishtr, 2017/05/16 23:36:42]

What about transforms that don't have effects?

[jaydasika, 2017/05/16 23:46:28]

The recursion variable not_axis_aligned_since_last_clip is updated for every
layer, not just for effects. So, if there is a non-axis aligned transform with
no effect, data_for_children->not_axis_aligned_since_last_clip should be true
for descendants. Am I missing something ?

[chrishtr, 2017/05/17 00:44:49]

Oh I see. AddEffectNodeIfNeeded is called unconditionally. It seems it
would be cleaner to update for children outside of this method, since it
is not specific to effect nodes.

[jaydasika, 2017/05/17 21:20:46]

The reason I put it here is to avoid duplicating the code. Since we create an
effect node for this, this code has to exist here also. I added it to property
tree builder too to update the children.

+  bool has_non_axis_aligned_clip =
+      not_axis_aligned_since_last_clip && LayerClipsSubtree(layer);
+  data_for_children->not_axis_aligned_since_last_clip =
+      !has_non_axis_aligned_clip;
+
   bool requires_node = is_root || has_transparency ||
                        has_potential_opacity_animation || has_proxied_opacity ||
+                       has_non_axis_aligned_clip ||
                        should_create_render_surface;
 
   int parent_id = data_from_ancestor.effect_tree_parent;
@@ -1273,6 +1285,7 @@ void BuildPropertyTreesTopLevelInternal(
   data_for_recursion.property_trees->clear();
   data_for_recursion.compound_transform_since_render_target = gfx::Transform();
   data_for_recursion.axis_align_since_render_target = true;
+  data_for_recursion.not_axis_aligned_since_last_clip = false;
   data_for_recursion.property_trees->transform_tree.set_device_scale_factor(
       device_scale_factor);
   data_for_recursion.safe_opaque_background_color = color;