Surface Synchronization: Distinguish between dependencies and references

cc/surfaces/surface_dependency_tracker.cc

 // Copyright 2016 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/surfaces/surface_dependency_tracker.h"
 
 #include "cc/surfaces/surface.h"
 #include "cc/surfaces/surface_info.h"
 #include "cc/surfaces/surface_manager.h"
 
@@ skipping 85 matching lines @@
 
   frames_since_deadline_set_.reset();
 }
 
 const BeginFrameArgs& SurfaceDependencyTracker::LastUsedBeginFrameArgs() const {
   return last_begin_frame_args_;
 }
 
 void SurfaceDependencyTracker::OnBeginFrameSourcePausedChanged(bool paused) {}
 
-void SurfaceDependencyTracker::OnReferencedSurfacesChanged(
-    Surface* surface,
-    const std::vector<SurfaceId>* active_referenced_surfaces,
-    const std::vector<SurfaceId>* pending_referenced_surfaces) {}
-
 void SurfaceDependencyTracker::OnSurfaceDiscarded(Surface* surface) {
   // If the surface being destroyed doesn't have a pending frame then we have
   // nothing to do here.
   if (!surface->HasPendingFrame())
     return;
 
   const CompositorFrame& pending_frame = surface->GetPendingFrame();
 
   DCHECK(!pending_frame.metadata.embedded_surfaces.empty());
 
@@ skipping 86 matching lines @@
       // A blocked surface may have been garbage collected during dependency
       // resolution.
       DCHECK(!observed_surfaces_by_id_.count(blocked_surface_by_id));
       continue;
     }
     blocked_surface->NotifySurfaceIdAvailable(surface_id);
   }
 }
 
 }  // namespace cc