Make first TouchStart and first TouchMove events on a flinging layer non-blocking

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"
 #include "content/common/input/event_with_latency_info.h"
 #include "content/common/input/input_event_ack_state.h"
 #include "content/common/input/input_event_dispatch_type.h"
 #include "content/common/input/web_input_event_queue.h"
+#include "content/public/common/content_features.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/events/blink/web_input_event_traits.h"
 #include "ui/events/latency_info.h"
 
 namespace content {
 
 class EventWithDispatchType : public ScopedWebInputEventWithLatencyInfo {
  public:
   EventWithDispatchType(ui::ScopedWebInputEvent event,
                         const ui::LatencyInfo& latency,
@@ skipping 100 matching lines @@
   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_;
 
   base::Lock event_queue_lock_;
   scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(MainThreadEventQueue);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_INPUT_MAIN_THREAD_EVENT_QUEUE_H_