gpu: Early return GpuCommandBufferStub::OnWaitSyncPoint() if the sync point is retired.

content/common/gpu/sync_point_manager.cc

 // Copyright (c) 2012 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 "content/common/gpu/sync_point_manager.h"
 
 #include "base/logging.h"
 
 namespace content {
 
@@ skipping 39 matching lines @@
     base::AutoLock lock(lock_);
     SyncPointMap::iterator it = sync_point_map_.find(sync_point);
     if (it != sync_point_map_.end()) {
       it->second.push_back(callback);
       return;
     }
   }
   callback.Run();
 }
 
+bool SyncPointManager::IsSyncPointRetired(uint32 sync_point) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  {
+    base::AutoLock lock(lock_);
+    SyncPointMap::iterator it = sync_point_map_.find(sync_point);
+    if (it != sync_point_map_.end())

[piman, 2014/01/08 21:43:54]

nit: just return it == sync_point_map_.end()

+      return false;
+  }
+  return true;
+}
+
 }  // namespace content