Revert "Revert "Allow clipping by scroll parents." and "Improve perf of CalculateDrawPropertiesInternal when there are no scroll parents.""

This reverts commit 97ada322de9f492e3f0d1741ac117fc42599451b.

This was a speculative perf revert; seems not to be the issue. Relanding.

Local tests with and without this patch on a Nexus 4 with and without my patch didn't show a perf regression (in fact, perf seemed to mysteriously improve -- I assume this is noise).

TBR=danakj@chromium.org
BUG=306926

Review URL: https://codereview.chromium.org/26135005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229221 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 25 insertions, 1 deletions

diff --git a/cc/layers/draw_properties.h b/cc/layers/draw_properties.h
index 06c8834..b81bec7 100644
--- a/cc/layers/draw_properties.h
+++ b/cc/layers/draw_properties.h
@@ -29,7 +29,13 @@ struct CC_EXPORT DrawProperties {
         num_descendants_that_draw_content(0),
         num_unclipped_descendants(0),
         can_draw_directly_to_backbuffer(false),
-        layer_or_descendant_has_copy_request(false) {}
+        layer_or_descendant_has_copy_request(false),
+        has_child_with_a_scroll_parent(false),
+        sorted_for_recursion(false),
+        index_of_first_descendants_addition(0),
+        num_descendants_added(0),
+        index_of_first_render_surface_layer_list_addition(0),
+        num_render_surfaces_added(0) {}
 
   // Transforms objects from content space to target surface space, where
   // this layer would be drawn.
@@ -97,6 +103,24 @@ struct CC_EXPORT DrawProperties {
   // If true, the layer or some layer in its sub-tree has a CopyOutputRequest
   // present on it.
   bool layer_or_descendant_has_copy_request;
+
+  // This is true if the layer has any direct child that has a scroll parent.
+  // This layer will not be the scroll parent in this case. This information
+  // lets us avoid work in CalculateDrawPropertiesInternal -- if none of our
+  // children have scroll parents, we will not need to recur out of order.
+  bool has_child_with_a_scroll_parent;
+
+  // This is true if the order (wrt to its siblings in the tree) in which the
+  // layer will be visited while computing draw properties has been determined.
+  bool sorted_for_recursion;
+
+  // If this layer is visited out of order, its contribution to the descendant
+  // and render surface layer lists will be put aside in a temporary list.
+  // These values will allow for an efficient reordering of these additions.
+  size_t index_of_first_descendants_addition;
+  size_t num_descendants_added;
+  size_t index_of_first_render_surface_layer_list_addition;
+  size_t num_render_surfaces_added;
 };
 
 }  // namespace cc