Teach main thread event queue about closures.

content/renderer/input/input_event_filter.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_RENDERER_INPUT_INPUT_EVENT_FILTER_H_
 #define CONTENT_RENDERER_INPUT_INPUT_EVENT_FILTER_H_
 
 #include <queue>
 #include <set>
 #include <unordered_map>
@@ skipping 45 matching lines @@
   // If INPUT_EVENT_ACK_STATE_NOT_CONSUMED is returned by the handler,
   // the original InputMsg_HandleInputEvent message will be delivered to
   // |main_listener| on the main thread.  (The "main thread" in this context is
   // the thread where the InputEventFilter was constructed.)  The responsibility
   // is left to the eventual handler to deliver the corresponding
   // InputHostMsg_HandleInputEvent_ACK.
   //
   void SetInputHandlerManager(InputHandlerManager*) override;
   void RegisterRoutingID(int routing_id) override;
   void UnregisterRoutingID(int routing_id) override;
+  void AssociateRenderFrameRoutingID(int render_frame_routing_id,
+                                     int render_view_routing_id) override;

[tdresser, 2017/03/30 17:46:16]

RegisterAssociatedRenderFrameRoutingID?

[dtapuska, 2017/03/30 19:45:51]

Done.

+  void QueueClosureForMainThreadEventQueue(
+      int routing_id,
+      const base::Closure& closure) override;
   void DidOverscroll(int routing_id,
                      const ui::DidOverscrollParams& params) override;
   void DidStopFlinging(int routing_id) override;
   void DispatchNonBlockingEventToMainThread(
       int routing_id,
       ui::WebScopedInputEvent event,
       const ui::LatencyInfo& latency_info) override;
 
   void NotifyInputEventHandled(int routing_id,
                                blink::WebInputEvent::Type type,
@@ skipping 19 matching lines @@
   void SendInputEventAck(int routing_id,
                          blink::WebInputEvent::Type type,
                          InputEventAckState ack_result,
                          uint32_t touch_event_id) override;
 
   void NeedsMainFrame(int routing_id) override;
 
  private:
   ~InputEventFilter() override;
 
-  void ForwardToHandler(const IPC::Message& message,
+  void ForwardToHandler(int routing_id,
+                        const IPC::Message& message,
                         base::TimeTicks received_time);
   void DidForwardToHandlerAndOverscroll(
       int routing_id,
       InputEventDispatchType dispatch_type,
       InputEventAckState ack_state,
       ui::WebScopedInputEvent event,
       const ui::LatencyInfo& latency_info,
       std::unique_ptr<ui::DidOverscrollParams> overscroll_params);
   void SendMessage(std::unique_ptr<IPC::Message> message);
   void SendMessageOnIOThread(std::unique_ptr<IPC::Message> message);
 
   scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
   base::Callback<void(const IPC::Message&)> main_listener_;
 
   // The sender_ only gets invoked on the thread corresponding to io_loop_.
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
   IPC::Sender* sender_;
 
   // The |input_handler_manager_| should outlive this class and
   // should only be called back on the |target_task_runner_|.
   scoped_refptr<base::SingleThreadTaskRunner> target_task_runner_;
   InputHandlerManager* input_handler_manager_;
 
   // Protects access to routes_.
   base::Lock routes_lock_;
 
-  // Indicates the routing_ids for which input events should be filtered.
+  // Indicates the routing ids for RenderViews for which input events
+  // should be filtered.
   std::set<int> routes_;
 
   using RouteQueueMap =
       std::unordered_map<int, scoped_refptr<MainThreadEventQueue>>;
+  // Maps RenderView routing ids to a MainThreadEventQueue.
   RouteQueueMap route_queues_;
 
+  using AssociatedRoutes = std::unordered_map<int, int>;
+  // Maps RenderFrame routing ids to RenderView routing ids so that
+  // events sent down the two routing pipes can be handled synchronously.
+  AssociatedRoutes associated_routes_;
+
   blink::scheduler::RendererScheduler* renderer_scheduler_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_INPUT_INPUT_EVENT_FILTER_H_