cc :: Move some tracking of layer_property_changed to main thread.

cc/layers/layer.cc

Index: cc/layers/layer.cc
diff --git a/cc/layers/layer.cc b/cc/layers/layer.cc
index 2430f9ca74906d6c7b9eb46a3441a561bfb318b1..4f4f17d687dd315c0417ef146d4e68f6e6c0349a 100644
--- a/cc/layers/layer.cc
+++ b/cc/layers/layer.cc
@@ -88,6 +88,7 @@ Layer::Layer(const LayerSettings& settings)
       force_render_surface_(false),
       transform_is_invertible_(true),
       has_render_surface_(false),
+      subtree_property_changed_(false),
       background_color_(0),
       opacity_(1.f),
       blend_mode_(SkXfermode::kSrcOver_Mode),
@@ -424,6 +425,7 @@ void Layer::RequestCopyOfOutput(
   if (request->IsEmpty())
     return;
   copy_requests_.push_back(std::move(request));
+  SetSubtreePropertyChanged();
   SetNeedsCommit();
 }
 
@@ -460,6 +462,7 @@ void Layer::SetMasksToBounds(bool masks_to_bounds) {
     return;
   masks_to_bounds_ = masks_to_bounds;
   SetNeedsCommit();
+  SetSubtreePropertyChanged();
 }
 
 void Layer::SetMaskLayer(Layer* mask_layer) {
@@ -477,6 +480,7 @@ void Layer::SetMaskLayer(Layer* mask_layer) {
     mask_layer_->SetParent(this);
     mask_layer_->SetIsMask(true);
   }
+  SetSubtreePropertyChanged();
   SetNeedsFullTreeSync();
 }
 
@@ -494,6 +498,7 @@ void Layer::SetReplicaLayer(Layer* layer) {
     replica_layer_->RemoveFromParent();
     replica_layer_->SetParent(this);
   }
+  SetSubtreePropertyChanged();
   SetNeedsFullTreeSync();
 }
 
@@ -610,6 +615,7 @@ void Layer::SetBlendMode(SkXfermode::Mode blend_mode) {
 
   blend_mode_ = blend_mode;
   SetNeedsCommit();
+  SetSubtreePropertyChanged();
 }
 
 void Layer::SetIsRootForIsolatedGroup(bool root) {
@@ -626,6 +632,7 @@ void Layer::SetContentsOpaque(bool opaque) {
     return;
   contents_opaque_ = opaque;
   SetNeedsCommit();
+  SetSubtreePropertyChanged();
 }
 
 void Layer::SetPosition(const gfx::PointF& position) {
@@ -1002,6 +1009,7 @@ void Layer::SetDoubleSided(bool double_sided) {
     return;
   double_sided_ = double_sided;
   SetNeedsCommit();
+  SetSubtreePropertyChanged();
 }
 
 void Layer::Set3dSortingContextId(int id) {
@@ -1010,6 +1018,7 @@ void Layer::Set3dSortingContextId(int id) {
     return;
   sorting_context_id_ = id;
   SetNeedsCommit();
+  SetSubtreePropertyChanged();
 }
 
 void Layer::SetTransformTreeIndex(int index) {
@@ -1093,6 +1102,7 @@ void Layer::SetShouldFlattenTransform(bool should_flatten) {
     return;
   should_flatten_transform_ = should_flatten;
   SetNeedsCommit();
+  SetSubtreePropertyChanged();
 }
 
 void Layer::SetUseParentBackfaceVisibility(bool use) {
@@ -1134,6 +1144,7 @@ void Layer::SetHideLayerAndSubtree(bool hide) {
 
   hide_layer_and_subtree_ = hide;
   SetNeedsCommit();
+  SetSubtreePropertyChanged();
 }
 
 void Layer::SetNeedsDisplayRect(const gfx::Rect& dirty_rect) {
@@ -1222,6 +1233,11 @@ void Layer::PushPropertiesTo(LayerImpl* layer) {
   layer->SetDrawsContent(DrawsContent());
   layer->SetHideLayerAndSubtree(hide_layer_and_subtree_);
   layer->SetHasRenderSurface(has_render_surface_);
+  // By the time we reach here, subtree_property_changed_ must have propagated
+  // to all descendants. So, it is enough to check it only for the current

[ajuma, 2016/02/10 15:31:32]

Also say why it will have already propagated to descendants.

[jaydasika, 2016/02/10 19:18:25]

Done.

+  // layer.
+  if (subtree_property_changed_)
+    layer->NoteLayerPropertyChanged();
   layer->SetForceRenderSurface(force_render_surface_);
   if (!layer->FilterIsAnimatingOnImplOnly() && !FilterIsAnimating())
     layer->SetFilters(filters_);
@@ -1359,6 +1375,7 @@ void Layer::PushPropertiesTo(LayerImpl* layer) {
 
   // Reset any state that should be cleared for the next update.
   stacking_order_changed_ = false;
+  subtree_property_changed_ = false;
   update_rect_ = gfx::Rect();
 
   needs_push_properties_ = false;
@@ -1494,6 +1511,7 @@ void Layer::LayerSpecificPropertiesToProto(proto::LayerProperties* proto) {
   base->set_draws_content(draws_content_);
   base->set_hide_layer_and_subtree(hide_layer_and_subtree_);
   base->set_has_render_surface(has_render_surface_);
+  base->set_subtree_property_changed(subtree_property_changed_);
 
   // TODO(nyquist): Add support for serializing FilterOperations for
   // |filters_| and |background_filters_|. See crbug.com/541321.
@@ -1582,6 +1600,7 @@ void Layer::FromLayerSpecificPropertiesProto(
   draws_content_ = base.draws_content();
   hide_layer_and_subtree_ = base.hide_layer_and_subtree();
   has_render_surface_ = base.has_render_surface();
+  subtree_property_changed_ = base.subtree_property_changed();
   masks_to_bounds_ = base.masks_to_bounds();
   main_thread_scrolling_reasons_ = base.main_thread_scrolling_reasons();
   non_fast_scrollable_region_ =
@@ -1733,6 +1752,10 @@ void Layer::SetHasRenderSurface(bool has_render_surface) {
   SetNeedsPushProperties();
 }
 
+void Layer::SetSubtreePropertyChanged() {
+  subtree_property_changed_ = true;
+}
+
 gfx::ScrollOffset Layer::ScrollOffsetForAnimation() const {
   return CurrentScrollOffset();
 }