Decouple GpuCompositorFrameSink from DisplayCompositor

cc/surfaces/surface_manager.cc

Index: cc/surfaces/surface_manager.cc
diff --git a/cc/surfaces/surface_manager.cc b/cc/surfaces/surface_manager.cc
index 94bdac6aceaf9382966fc5dedcc45262303c0837..8d924c2189b723b0491879a7a4b6e76e6ed0e872 100644
--- a/cc/surfaces/surface_manager.cc
+++ b/cc/surfaces/surface_manager.cc
@@ -224,6 +224,26 @@ void SurfaceManager::RemoveSurfaceReference(const SurfaceId& parent_id,
   GarbageCollectSurfaces();
 }
 
+void SurfaceManager::AddSurfaceReferences(
+    const std::vector<SurfaceReference>& references) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  for (const auto& reference : references) {

[kylechar, 2017/01/25 15:54:33]

Get rid of {} since the loop body is only one line.

+    AddSurfaceReference(reference.parent_id(), reference.child_id());
+  }
+}
+
+void SurfaceManager::RemoveSurfaceReferences(
+    const std::vector<SurfaceReference>& references) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  // TODO(kylechar): Each remove reference can trigger GC, it would be better if

[kylechar, 2017/01/25 15:54:33]

We can easily make this comment a reality now. Run GarbageCollectSurfaces() once
after you go through the list of references to remove and remove the call from
GarbageCollectSurfaces().

+  // we GC only once if removing multiple references.
+  for (const auto& reference : references) {

[kylechar, 2017/01/25 15:54:33]

Get rid of {} since the loop body is only one line.

+    RemoveSurfaceReference(reference.parent_id(), reference.child_id());
+  }
+}
+
 size_t SurfaceManager::GetSurfaceReferenceCount(
     const SurfaceId& surface_id) const {
   auto iter = child_to_parent_refs_.find(surface_id);