Implement Main Thread RAF Aligned Input

content/renderer/input/main_thread_event_queue.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 CONTENT_RENDERER_INPUT_MAIN_THREAD_EVENT_QUEUE_H_
 #define CONTENT_RENDERER_INPUT_MAIN_THREAD_EVENT_QUEUE_H_
 
 #include <deque>
 #include "base/feature_list.h"
 #include "content/common/content_export.h"
@@ skipping 12 matching lines @@
 class EventWithDispatchType : public ScopedWebInputEventWithLatencyInfo {
  public:
   EventWithDispatchType(ui::ScopedWebInputEvent event,
                         const ui::LatencyInfo& latency,
                         InputEventDispatchType dispatch_type);
   ~EventWithDispatchType();
   bool CanCoalesceWith(const EventWithDispatchType& other) const
       WARN_UNUSED_RESULT;
   void CoalesceWith(const EventWithDispatchType& other);
 
-  const std::deque<uint32_t>& eventsToAck() const { return eventsToAck_; }
+  const std::deque<uint32_t>& coalescedEventIds() const {
+    return coalesced_event_ids_;
+  }
   InputEventDispatchType dispatchType() const { return dispatch_type_; }
+  base::TimeTicks creationTimestamp() const { return creation_timestamp_; }
+  base::TimeTicks coalescedTimestamp() const { return coalesced_timestamp_; }
 
  private:
   InputEventDispatchType dispatch_type_;
 
-  // |eventsToAck_| contains the unique touch event id to be acked. If
+  // |coalesced_event_ids_| contains the unique touch event id to be acked. If

[tdresser, 2016/08/24 13:43:00]

event id -> event ids

[dtapuska, 2016/08/24 17:10:06]

done.

   // the events are TouchEvents the value will be 0. More importantly for

[tdresser, 2016/08/24 13:43:00]

Is this comment correct? Should it be "If the events areN'T TouchEvents?"

[dtapuska, 2016/08/24 17:10:06]

done.

   // those cases the deque ends up containing how many additional ACKs
   // need to be sent.
-  std::deque<uint32_t> eventsToAck_;
+  std::deque<uint32_t> coalesced_event_ids_;
+  base::TimeTicks creation_timestamp_;
+  base::TimeTicks coalesced_timestamp_;

[tdresser, 2016/08/24 13:43:00]

Maybe:
last_coalesced_timestamp_
or
most_recent_coalesced_timestamp_
?

[dtapuska, 2016/08/24 17:10:06]

done

 };
 
 class CONTENT_EXPORT MainThreadEventQueueClient {
  public:
   // Handle an |event| that was previously queued (possibly
   // coalesced with another event) to the |routing_id|'s
   // channel. Implementors must implement this callback.
   virtual void HandleEventOnMainThread(
       int routing_id,
       const blink::WebInputEvent* event,
       const ui::LatencyInfo& latency,
       InputEventDispatchType dispatch_type) = 0;
 
   virtual void SendInputEventAck(int routing_id,
                                  blink::WebInputEvent::Type type,
                                  InputEventAckState ack_result,
                                  uint32_t touch_event_id) = 0;
+  virtual void NeedsMainFrame(int routing_id) = 0;
 };
 
 // MainThreadEventQueue implements a queue for events that need to be
 // queued between the compositor and main threads. This queue is managed
 // by a lock where events are enqueued by the compositor thread
 // and dequeued by the main thread.
 //
 // Below some example flows are how the code behaves.
 // Legend: B=Browser, C=Compositor, M=Main Thread, NB=Non-blocking
 //         BL=Blocking, PT=Post Task, ACK=Acknowledgement
@@ skipping 25 matching lines @@
 //                  (deque)
 //   <-------(ACK)------
 //
 class CONTENT_EXPORT MainThreadEventQueue
     : public base::RefCountedThreadSafe<MainThreadEventQueue> {
  public:
   MainThreadEventQueue(
       int routing_id,
       MainThreadEventQueueClient* client,
       const scoped_refptr<base::SingleThreadTaskRunner>& main_task_runner,
-      blink::scheduler::RendererScheduler* renderer_scheduler);
+      blink::scheduler::RendererScheduler* renderer_scheduler,
+      bool handle_raf_aligned_input);
 
   // Called once the compositor has handled |event| and indicated that it is
   // a non-blocking event to be queued to the main thread.
   bool HandleEvent(ui::ScopedWebInputEvent event,
                    const ui::LatencyInfo& latency,
                    InputEventDispatchType dispatch_type,
                    InputEventAckState ack_result);
+  void DispatchRafAlignedInput();
 
   // Call once the main thread has handled an outstanding |type| event
   // in flight.
   void EventHandled(blink::WebInputEvent::Type type,
                     InputEventAckState ack_result);
 
   void set_is_flinging(bool is_flinging) { is_flinging_ = is_flinging; }
 
  private:
   friend class base::RefCountedThreadSafe<MainThreadEventQueue>;
   ~MainThreadEventQueue();
   void QueueEvent(std::unique_ptr<EventWithDispatchType> event);
   void SendEventNotificationToMainThread();
-  void PopEventOnMainThread();
+  void DispatchSingleEvent();
+  void DispatchInFlightEvent();
+  void PossiblyScheduleMainFrame();
+
   void SendEventToMainThread(const blink::WebInputEvent* event,
                              const ui::LatencyInfo& latency,
                              InputEventDispatchType original_dispatch_type);
 
   friend class MainThreadEventQueueTest;
   int routing_id_;
   MainThreadEventQueueClient* client_;
   WebInputEventQueue<EventWithDispatchType> events_;
   std::unique_ptr<EventWithDispatchType> in_flight_event_;
   bool is_flinging_;
   bool last_touch_start_forced_nonblocking_due_to_fling_;
   bool enable_fling_passive_listener_flag_;
+  bool handle_raf_aligned_input_;
+  bool sent_main_frame_request_;

[tdresser, 2016/08/24 13:42:59]

We should indicate which members should only be accessed through the
event_queue_lock_.

It might even be worth bundling them into a struct, though if it's only two
members, it's probably be fine.

[dtapuska, 2016/08/24 17:10:06]

done

 
   base::Lock event_queue_lock_;
   scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
   blink::scheduler::RendererScheduler* renderer_scheduler_;
 
   DISALLOW_COPY_AND_ASSIGN(MainThreadEventQueue);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_INPUT_MAIN_THREAD_EVENT_QUEUE_H_