cc : Stop pushing layers from hidden subtrees at commit

cc/layers/layer.cc

Index: cc/layers/layer.cc
diff --git a/cc/layers/layer.cc b/cc/layers/layer.cc
index d3100f3daa802322ca072e5be186709b65020bce..c8e35cd3c73cebc4bdbc11da7700be1ba91ff233 100644
--- a/cc/layers/layer.cc
+++ b/cc/layers/layer.cc
@@ -86,6 +86,7 @@ Layer::Layer()
       property_tree_sequence_number_(-1),
       should_flatten_transform_from_property_tree_(false),
       draws_content_(false),
+      is_hidden_(false),
       use_local_transform_for_backface_visibility_(false),
       should_check_backface_visibility_(false),
       force_render_surface_for_testing_(false),
@@ -1127,6 +1128,14 @@ bool Layer::IsSnapped() {
   return scrollable();
 }
 
+bool Layer::IsSurfaceLayer() const {
+  return false;
+}
+
+const SurfaceId* Layer::GetSurfaceId() const {
+  return nullptr;
+}
+
 void Layer::PushPropertiesTo(LayerImpl* layer) {
   TRACE_EVENT0("cc", "Layer::PushPropertiesTo");
   DCHECK(layer_tree_host_);
@@ -1283,6 +1292,17 @@ void Layer::didUpdateMainThreadScrollingReasons() {
     inputs_.client->didUpdateMainThreadScrollingReasons();
 }
 
+void Layer::SetIsHidden(bool is_hidden) {
+  DCHECK(layer_tree_host_);
+  if (is_hidden == is_hidden_)
+    return;
+  is_hidden_ = is_hidden;
+  // We don't push layers that are hidden to compositor thread at commit. So,
+  // we need a full tree sync when is_hidden changes.
+  layer_tree_host_->SetNeedsFullTreeSync();
+  SetNeedsPushProperties();
+}
+
 void Layer::SetSubtreePropertyChanged() {
   if (subtree_property_changed_)
     return;