Move FrameSink hierarchy registration to DisplayCompositor interface

cc/surfaces/compositor_frame_sink_support.cc

Index: cc/surfaces/compositor_frame_sink_support.cc
diff --git a/cc/surfaces/compositor_frame_sink_support.cc b/cc/surfaces/compositor_frame_sink_support.cc
index 6cb2414b1cdd324ec23d10e84aea187455dab3d8..96508cd305d7d4c0cd6a4ab86b2e83956407ebaa 100644
--- a/cc/surfaces/compositor_frame_sink_support.cc
+++ b/cc/surfaces/compositor_frame_sink_support.cc
@@ -50,11 +50,6 @@ CompositorFrameSinkSupport::~CompositorFrameSinkSupport() {
       reference_tracker_.current_surface_id().is_valid())
     RemoveTopLevelRootReference(reference_tracker_.current_surface_id());
 
-  for (auto& child_frame_sink_id : child_frame_sinks_) {
-    DCHECK(child_frame_sink_id.is_valid());
-    surface_manager_->UnregisterFrameSinkHierarchy(frame_sink_id_,
-                                                   child_frame_sink_id);
-  }
   // SurfaceFactory's destructor will attempt to return resources which will
   // call back into here and access |client_| so we should destroy
   // |surface_factory_|'s resources early on.
@@ -152,23 +147,6 @@ void CompositorFrameSinkSupport::DidReceiveCompositorFrameAck() {
   }
 }
 
-void CompositorFrameSinkSupport::AddChildFrameSink(
-    const FrameSinkId& child_frame_sink_id) {
-  child_frame_sinks_.insert(child_frame_sink_id);
-  surface_manager_->RegisterFrameSinkHierarchy(frame_sink_id_,
-                                               child_frame_sink_id);
-}
-
-void CompositorFrameSinkSupport::RemoveChildFrameSink(
-    const FrameSinkId& child_frame_sink_id) {
-  auto it = child_frame_sinks_.find(child_frame_sink_id);
-  DCHECK(it != child_frame_sinks_.end());
-  DCHECK(it->is_valid());
-  surface_manager_->UnregisterFrameSinkHierarchy(frame_sink_id_,
-                                                 child_frame_sink_id);
-  child_frame_sinks_.erase(it);
-}
-
 void CompositorFrameSinkSupport::ForceReclaimResources() {
   surface_factory_.ClearSurface();
 }