Make cc::Display not own its BeginFrameSource

blimp/client/app/compositor/browser_compositor.h

Index: blimp/client/app/compositor/browser_compositor.h
diff --git a/blimp/client/app/compositor/browser_compositor.h b/blimp/client/app/compositor/browser_compositor.h
index cb0828f477ff98058f4c6f82beacf80c02edf28b..05cb73eeaa453537e9cae51164172d18ae19446b 100644
--- a/blimp/client/app/compositor/browser_compositor.h
+++ b/blimp/client/app/compositor/browser_compositor.h
@@ -8,6 +8,7 @@
 #include "base/macros.h"
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
+#include "cc/scheduler/begin_frame_source.h"
 #include "cc/trees/layer_tree_host_client.h"
 #include "cc/trees/layer_tree_host_single_thread_client.h"
 #include "ui/gfx/geometry/size.h"
@@ -83,6 +84,7 @@ class BrowserCompositor : public cc::LayerTreeHostClient,
   gfx::AcceleratedWidget widget_;
   bool output_surface_request_pending_;
   std::unique_ptr<cc::Display> display_;
+  std::unique_ptr<cc::SyntheticBeginFrameSource> begin_frame_source_;
 
   gfx::Size viewport_size_in_px_;