cc : Store surface layer ids on LayerTreeHost and push them at commit

cc/trees/tree_synchronizer.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/tree_synchronizer.h"
 
 #include <stddef.h>
 
 #include <set>
 
@@ skipping 114 matching lines @@
     LayerImpl* layer_impl = impl_tree->LayerById(layer->id());
     DCHECK(layer_impl);
     layer->PushPropertiesTo(layer_impl);
   }
 }
 
 void TreeSynchronizer::PushLayerProperties(LayerTreeImpl* pending_tree,
                                            LayerTreeImpl* active_tree) {
   PushLayerPropertiesInternal(pending_tree->LayersThatShouldPushProperties(),
                               active_tree);
+  if (pending_tree->needs_surface_ids_sync()) {

[enne (OOO), 2017/05/24 18:44:54]

Should this be in LayerTreeImpl::PushPropertiesTo and not TreeSynchronizer?

[jaydasika, 2017/05/24 21:39:54]

Done.

+    active_tree->ClearSurfaceLayerIds();
+    active_tree->SetSurfaceLayerIds(pending_tree->SurfaceLayerIds());
+    // Reset for next update
+    pending_tree->set_needs_surface_ids_sync(false);
+  }
 }
 
 void TreeSynchronizer::PushLayerProperties(LayerTreeHost* host_tree,
                                            LayerTreeImpl* impl_tree) {
   PushLayerPropertiesInternal(host_tree->LayersThatShouldPushProperties(),
                               impl_tree);
+  if (host_tree->needs_surface_ids_sync()) {

[enne (OOO), 2017/05/24 18:44:54]

Similarly, should this be in LayerTreeHost::FinishCommitOnImplThread and not
TreeSynchronizer?

[jaydasika, 2017/05/24 21:39:54]

Done.

+    impl_tree->ClearSurfaceLayerIds();
+    impl_tree->SetSurfaceLayerIds(host_tree->SurfaceLayerIds());
+    // Reset for next update
+    host_tree->set_needs_surface_ids_sync(false);
+  }
 }
 
 }  // namespace cc