Implement compositor thread VSync aligned event queue

ui/events/blink/input_handler_proxy.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 UI_EVENTS_BLINK_INPUT_HANDLER_PROXY_H_
 #define UI_EVENTS_BLINK_INPUT_HANDLER_PROXY_H_
 
 #include <memory>
 
 #include "base/containers/hash_tables.h"
 #include "base/macros.h"
 #include "cc/input/input_handler.h"
 #include "third_party/WebKit/public/platform/WebGestureCurve.h"
 #include "third_party/WebKit/public/platform/WebGestureCurveTarget.h"
 #include "third_party/WebKit/public/platform/WebInputEvent.h"
 #include "third_party/WebKit/public/web/WebActiveWheelFlingParameters.h"
+#include "ui/events/blink/blink_features.h"
 #include "ui/events/blink/input_scroll_elasticity_controller.h"
 #include "ui/events/blink/scoped_web_input_event.h"
 #include "ui/events/blink/synchronous_input_handler_proxy.h"
 
 namespace ui {
 
 namespace test {
 class InputHandlerProxyTest;
+class InputHandlerProxyEventQueueTest;
 }
 
+class CompositorThreadEventQueue;
+class EventWithCallback;
 class InputHandlerProxyClient;
 class InputScrollElasticityController;
 class SynchronousInputHandler;
 class SynchronousInputHandlerProxy;
 struct DidOverscrollParams;
 
 // This class is a proxy between the blink web input events for a WebWidget and
 // the compositor's input handling logic. InputHandlerProxy instances live
 // entirely on the compositor thread. Each InputHandler instance handles input
 // events intended for a specific WebWidget.
@@ skipping 36 matching lines @@
   void Animate(base::TimeTicks time) override;
   void MainThreadHasStoppedFlinging() override;
   void ReconcileElasticOverscrollAndRootScroll() override;
   void UpdateRootLayerStateForSynchronousInputHandler(
       const gfx::ScrollOffset& total_scroll_offset,
       const gfx::ScrollOffset& max_scroll_offset,
       const gfx::SizeF& scrollable_size,
       float page_scale_factor,
       float min_page_scale_factor,
       float max_page_scale_factor) override;
+  void DeliverInputForBeginFrame() override;
 
   // SynchronousInputHandlerProxy implementation.
   void SetOnlySynchronouslyAnimateRootFlings(
       SynchronousInputHandler* synchronous_input_handler) override;
   void SynchronouslyAnimate(base::TimeTicks time) override;
   void SynchronouslySetRootScrollOffset(
       const gfx::ScrollOffset& root_offset) override;
   void SynchronouslyZoomBy(float magnify_delta,
                            const gfx::Point& anchor) override;
 
   // blink::WebGestureCurveTarget implementation.
   bool scrollBy(const blink::WebFloatSize& offset,
                 const blink::WebFloatSize& velocity) override;
 
   bool gesture_scroll_on_impl_thread_for_testing() const {
     return gesture_scroll_on_impl_thread_;
   }
 
  protected:
   void RecordMainThreadScrollingReasons(blink::WebGestureDevice device,
                                         uint32_t reasons);
 
  private:
   friend class test::InputHandlerProxyTest;
+  friend class test::InputHandlerProxyEventQueueTest;
+
+  void DispatchSingleInputEvent(std::unique_ptr<EventWithCallback>);
+  void DispatchQueuedInputEvents();
 
   // Helper functions for handling more complicated input events.
   EventDisposition HandleMouseWheel(
       const blink::WebMouseWheelEvent& event);
   EventDisposition ScrollByMouseWheel(
       const blink::WebMouseWheelEvent& event,
       cc::EventListenerProperties listener_properties);
   EventDisposition HandleGestureScrollBegin(
       const blink::WebGestureEvent& event);
   EventDisposition HandleGestureScrollUpdate(
@@ skipping 104 matching lines @@
   int32_t touch_start_result_;
 
   base::TimeTicks last_fling_animate_time_;
 
   // Used to record overscroll notifications while an event is being
   // dispatched.  If the event causes overscroll, the overscroll metadata can be
   // bundled in the event ack, saving an IPC.  Note that we must continue
   // supporting overscroll IPC notifications due to fling animation updates.
   std::unique_ptr<DidOverscrollParams> current_overscroll_params_;
 
+  std::unique_ptr<CompositorThreadEventQueue> event_queue_;
+  bool has_ongoing_compositor_scroll_pinch_;
+  bool compositor_event_queue_enabled_;

[dtapuska, 2016/11/09 21:28:05]

Can we use the existence of the event_queue_ as knowledge we are supporting it?
ie; I don't like states that two values imply each other. For example
compositor_event_queue_enabled_ could be true but event_queue_ nullptr

[chongz, 2016/11/11 21:52:05]

Done.

+
+  // Testing only
+  static std::unique_ptr<base::TimeTicks> testing_timestamp_now_;
+
   DISALLOW_COPY_AND_ASSIGN(InputHandlerProxy);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_BLINK_INPUT_HANDLER_PROXY_H_