Add hooks for flushing input from BeginFrame dispatch on Aura

content/browser/renderer_host/begin_frame_observer_proxy.h

 // Copyright 2015 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 CONTENT_BROWSER_RENDERER_HOST_BEGIN_FRAME_OBSERVER_PROXY_H_
 #define CONTENT_BROWSER_RENDERER_HOST_BEGIN_FRAME_OBSERVER_PROXY_H_
 
 #include "content/common/content_export.h"
 #include "ui/compositor/compositor.h"
 #include "ui/compositor/compositor_observer.h"
@@ skipping 14 matching lines @@
 // This class is used to manage all of the RenderWidgetHostView state and
 // functionality that is associated with BeginFrame message handling.
 class CONTENT_EXPORT BeginFrameObserverProxy
     : public ui::CompositorBeginFrameObserver,
       public ui::CompositorObserver {
  public:
   explicit BeginFrameObserverProxy(BeginFrameObserverProxyClient* client);
   ~BeginFrameObserverProxy() override;
 
   void SetNeedsBeginFrames(bool needs_begin_frames);
+  void SetNeedsOneBeginFrame();
 
   void SetCompositor(ui::Compositor* compositor);
   void ResetCompositor();
 
   // Overridden from ui::CompositorBeginFrameObserver:
   void OnSendBeginFrame(const cc::BeginFrameArgs& args) override;
 
   // Overridden from ui::CompositorObserver:
   // TODO(simonhong): Stop overriding ui::CompositorObserver. We need to make
   // sure that this class should be destroyed before ui::Compositor.
   void OnCompositingDidCommit(ui::Compositor* compositor) override {}
   void OnCompositingStarted(ui::Compositor* compositor,
                             base::TimeTicks start_time) override {}
   void OnCompositingEnded(ui::Compositor* compositor) override {}
   void OnCompositingAborted(ui::Compositor* compositor) override {}
   void OnCompositingLockStateChanged(ui::Compositor* compositor) override {}
   void OnCompositingShuttingDown(ui::Compositor* compositor) override;
 
  private:
+  void UpdateBeginFrameObservation();
   void StartObservingBeginFrames();
   void StopObservingBeginFrames();
 
   // True when RenderWidget needs a BeginFrame message.
   bool needs_begin_frames_;
 
+  // True when the RenderWidget needs just one BeginFrame message.
+  bool needs_one_begin_frame_;
+
+  // Whether we're subscribed as a BeginFrame observer.
+  bool observing_begin_frames_;
+
   // Used whether to send begin frame to client or not. When |args| from
   // Compositor is different from this, send to client.
   cc::BeginFrameArgs last_sent_begin_frame_args_;
 
   BeginFrameObserverProxyClient* client_;
   ui::Compositor* compositor_;
 
   DISALLOW_COPY_AND_ASSIGN(BeginFrameObserverProxy);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_BEGIN_FRAME_OBSERVER_PROXY_H_