Make cc::Display not own its BeginFrameSource

cc/test/test_delegating_output_surface.h

 // 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.
 
 #ifndef CC_TEST_TEST_DELEGATING_OUTPUT_SURFACE_H_
 #define CC_TEST_TEST_DELEGATING_OUTPUT_SURFACE_H_
 
 #include "base/memory/weak_ptr.h"
 #include "cc/output/output_surface.h"
 #include "cc/output/renderer_settings.h"
@@ skipping 72 matching lines @@
   void DidDrawCallback(bool synchronous);
 
   // TODO(danakj): These don't need to be stored in unique_ptrs when
   // OutputSurface is owned/destroyed on the compositor thread.
   std::unique_ptr<SurfaceManager> surface_manager_;
   std::unique_ptr<SurfaceIdAllocator> surface_id_allocator_;
   SurfaceId delegated_surface_id_;
 
   // Uses surface_manager_.
   std::unique_ptr<SurfaceFactory> surface_factory_;
-
-  // Uses surface_manager_.
+  std::unique_ptr<SyntheticBeginFrameSource> begin_frame_source_;
   std::unique_ptr<Display> display_;
 
   bool bound_ = false;
   TestDelegatingOutputSurfaceClient* test_client_ = nullptr;
   gfx::Size enlarge_pass_texture_amount_;
 
   std::vector<std::unique_ptr<CopyOutputRequest>> copy_requests_;
 
   base::WeakPtrFactory<TestDelegatingOutputSurface> weak_ptrs_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_TEST_DELEGATING_OUTPUT_SURFACE_H_