cc: Replace LayerImpl with ScrollNode when updating scrolling info.

ScrollState, DistributeScrollDelta and ScrollAnimated use scroll_node
instead of LayerImpl.

Move user_scrollable, clip_height and currently_scrolling_layer to
scroll_tree.

Use scroll_node->owner_id to create animation, but still use LayerImpl
for the deprecated LayerAnimationController code path.

LayerImpl::scroll_offset_ is the only left-over.

BUG=568830
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1708763002

Cr-Commit-Position: refs/heads/master@{#376838}

1 files changed, 10 insertions, 1 deletions

diff --git a/cc/proto/property_tree.proto b/cc/proto/property_tree.proto
index 7622d68..bae0efa 100644
--- a/cc/proto/property_tree.proto
+++ b/cc/proto/property_tree.proto
@@ -97,7 +97,7 @@ message EffectNodeData {
 }
 
 // Proto for struct ScrollNodeData
-// NEXT ID: 9
+// NEXT ID: 15
 message ScrollNodeData {
   optional bool scrollable = 1;
   optional int32 main_thread_scrolling_reasons = 2;
@@ -109,6 +109,9 @@ message ScrollNodeData {
   optional bool is_outer_viewport_scroll_layer = 8;
   optional Vector2dF offset_to_transform_parent = 9;
   optional bool should_flatten = 10;
+  optional bool user_scrollable_horizontal = 13;
+  optional bool user_scrollable_vertical = 14;
+  optional int64 element_id = 12;
   optional int64 transform_id = 11;
 }
 
@@ -149,6 +152,12 @@ message PropertyTree {
   // PropertyTree. Only one of these fields should be set, depending on the type
   // of this property tree.
   optional TransformTreeData transform_tree_data = 1000;
+  optional ScrollTreeData scroll_tree_data = 1001;
+}
+
+// Proto for data members of class ScrollTree
+message ScrollTreeData {
+  optional int64 currently_scrolling_node_id = 1;
 }
 
 // Proto for data members of class TransformTree.