Signal input flush when all flings have terminated

content/browser/renderer_host/input/input_router.h

 // Copyright 2013 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_INPUT_INPUT_ROUTER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_ROUTER_H_
 
 #include "base/basictypes.h"
 #include "content/browser/renderer_host/event_with_latency_info.h"
 #include "content/common/input/input_event_ack_state.h"
 #include "content/public/browser/native_web_keyboard_event.h"
 #include "ipc/ipc_listener.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 
 namespace content {
 
 class InputRouterClient;
 
 // The InputRouter allows the embedder to customize how input events are
 // sent to the renderer, and how responses are dispatched to the browser.
 // While the router should respect the relative order in which events are
 // received, it is free to customize when those events are dispatched.
 class InputRouter : public IPC::Listener {
  public:
   ~InputRouter() override {}
 
-  // Should be called only in response to |SetNeedsFlush| requests made via
-  // the |InputRouterClient|.
-  virtual void Flush() = 0;
-
   // Send and take ownership of the the given InputMsg_*. This should be used
   // only for event types not associated with a WebInputEvent.  Returns true on
   // success and false otherwise.
   virtual bool SendInput(scoped_ptr<IPC::Message> message) = 0;
 
   // WebInputEvents
   virtual void SendMouseEvent(
       const MouseEventWithLatencyInfo& mouse_event) = 0;
   virtual void SendWheelEvent(
       const MouseWheelEventWithLatencyInfo& wheel_event) = 0;
@@ skipping 11 matching lines @@
 
   // Allow the router to make more informed input handling decisions based on
   // the current view.
   enum ViewFlags {
     VIEW_FLAGS_NONE   = 0,
     FIXED_PAGE_SCALE  = 1 << 0,
     MOBILE_VIEWPORT   = 1 << 1
   };
   virtual void OnViewUpdated(int view_flags) = 0;
 
+  // Request a notification from the input router when all events have been
+  // fully dispatched and there are no longer any pending events.
+  // Note: This may trigger a synchronous notification if the router is empty.
+  virtual void RequestNotificationWhenFlushed() = 0;
+
+  // Whether there are any events pending dispatch to or ack from the renderer.
   virtual bool HasPendingEvents() const = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_ROUTER_H_