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

content/common/gpu/gpu_command_buffer_stub.cc

Index: content/common/gpu/gpu_command_buffer_stub.cc
diff --git a/content/common/gpu/gpu_command_buffer_stub.cc b/content/common/gpu/gpu_command_buffer_stub.cc
index 44eaf90cc85fb3634f118576f716f868d6d02ccf..181edc57825a2f89e435e74087a5e2518d2c32cc 100644
--- a/content/common/gpu/gpu_command_buffer_stub.cc
+++ b/content/common/gpu/gpu_command_buffer_stub.cc
@@ -768,13 +768,16 @@ void GpuCommandBufferStub::OnRetireSyncPoint(uint32 sync_point) {
 }
 
 bool GpuCommandBufferStub::OnWaitSyncPoint(uint32 sync_point) {
+  GpuChannelManager* manager = channel_->gpu_channel_manager();
+  if (manager->sync_point_manager()->IsSyncPointRetired(sync_point))
+    return true;
+
   if (sync_point_wait_count_ == 0) {
     TRACE_EVENT_ASYNC_BEGIN1("gpu", "WaitSyncPoint", this,
                              "GpuCommandBufferStub", this);
   }
   scheduler_->SetScheduled(false);
   ++sync_point_wait_count_;
-  GpuChannelManager* manager = channel_->gpu_channel_manager();
   manager->sync_point_manager()->AddSyncPointCallback(
       sync_point,
       base::Bind(&GpuCommandBufferStub::OnSyncPointRetired,