cc : Make tree synchronization independent of layer tree hierarchy (2)

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index d5f9b58577ab099d8d980a2fd152ae6da1e40528..ef27f9428f7230e52e041a9ab658bdfdd231c683 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -482,7 +482,14 @@ void LayerTreeHost::FinishCommitOnImplThread(LayerTreeHostImpl* host_impl) {
 
   {
     TRACE_EVENT0("cc", "LayerTreeHost::PushProperties");
-    TreeSynchronizer::PushProperties(root_layer(), sync_tree->root_layer());
+
+    std::unordered_set<Layer*> layers_that_should_push_properties =
+        layers_that_should_push_properties_;
+    for (auto layer : layers_that_should_push_properties) {
+      LayerImpl* sync_tree_layer = sync_tree->LayerById(layer->id());
+      DCHECK(sync_tree_layer);
+      layer->PushPropertiesTo(sync_tree_layer);
+    }
 
     if (animation_host_) {
       TRACE_EVENT0("cc", "LayerTreeHost::AnimationHost::PushProperties");
@@ -1259,6 +1266,23 @@ Layer* LayerTreeHost::LayerById(int id) const {
   return iter != layer_id_map_.end() ? iter->second : NULL;
 }
 
+void LayerTreeHost::AddLayerShouldPushProperties(Layer* layer) {
+  layers_that_should_push_properties_.insert(layer);
+}
+
+void LayerTreeHost::RemoveLayerShouldPushProperties(Layer* layer) {
+  layers_that_should_push_properties_.erase(layer);
+}
+
+std::unordered_set<Layer*>& LayerTreeHost::LayersThatShouldPushProperties() {
+  return layers_that_should_push_properties_;
+}
+
+bool LayerTreeHost::LayerNeedsPushPropertiesForTesting(Layer* layer) {
+  return layers_that_should_push_properties_.find(layer) !=
+         layers_that_should_push_properties_.end();
+}
+
 void LayerTreeHost::RegisterLayer(Layer* layer) {
   DCHECK(!LayerById(layer->id()));
   DCHECK(!in_paint_layer_contents_);
@@ -1270,6 +1294,7 @@ void LayerTreeHost::RegisterLayer(Layer* layer) {
 void LayerTreeHost::UnregisterLayer(Layer* layer) {
   DCHECK(LayerById(layer->id()));
   DCHECK(!in_paint_layer_contents_);
+  RemoveLayerShouldPushProperties(layer);

[ajuma, 2016/03/18 14:33:16]

Do we have a test that removes a layer needing push properties from its host,
verifying that this layer's id is no longer in that host's set of layers needing
push properties?

[jaydasika, 2016/03/19 02:17:58]

There are many tests that check this implicitly. More than 40 tests were
crashing when InvalidatePropertyTrees in layer.cc was trying to add the layer
back to the old layer tree host's set. 

   if (animation_host_)
     animation_host_->UnregisterLayer(layer->id(), LayerTreeType::ACTIVE);
   layer_id_map_.erase(layer->id());
@@ -1459,8 +1484,8 @@ bool LayerTreeHost::IsRemoteClient() const {
          task_runner_provider_->HasImplThread();
 }
 
-void LayerTreeHost::ToProtobufForCommit(proto::LayerTreeHost* proto) const {
-  // Not all fields are serialized, as they are eiher not needed for a commit,
+void LayerTreeHost::ToProtobufForCommit(proto::LayerTreeHost* proto) {
+  // Not all fields are serialized, as they are either not needed for a commit,
   // or implementation isn't ready yet.
   // Unsupported items:
   // - animations
@@ -1487,7 +1512,11 @@ void LayerTreeHost::ToProtobufForCommit(proto::LayerTreeHost* proto) const {
       meta_information_sequence_number_);
   LayerProtoConverter::SerializeLayerHierarchy(root_layer_,
                                                proto->mutable_root_layer());
-  LayerProtoConverter::SerializeLayerProperties(root_layer_.get(),
+  // layers_that_should_push_properties_ should be serialized before layer
+  // properties because the it is cleared during the properties serialization.
+  for (auto layer : layers_that_should_push_properties_)
+    proto->add_layers_that_should_push_properties(layer->id());
+  LayerProtoConverter::SerializeLayerProperties(this,
                                                 proto->mutable_layer_updates());
   proto->set_hud_layer_id(hud_layer_ ? hud_layer_->id() : Layer::INVALID_ID);
   debug_state_.ToProtobuf(proto->mutable_debug_state());
@@ -1556,6 +1585,8 @@ void LayerTreeHost::FromProtobufForCommit(const proto::LayerTreeHost& proto) {
   LayerTreeHostCommon::CallFunctionForSubtree(
       root_layer(),
       [this](Layer* layer) { layer_id_map_[layer->id()] = layer; });
+  for (auto layer_id : proto.layers_that_should_push_properties())
+    layers_that_should_push_properties_.insert(layer_id_map_[layer_id]);
 
   LayerProtoConverter::DeserializeLayerProperties(root_layer_.get(),
                                                   proto.layer_updates());