Report user actions when gesture starts and stops in user_model.

components/scheduler/renderer/user_model.h

 // Copyright 2015 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 COMPONENTS_SCHEDULER_RENDERER_USER_MODEL_H_
 #define COMPONENTS_SCHEDULER_RENDERER_USER_MODEL_H_
 
 #include "base/macros.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_argument.h"
 #include "components/scheduler/renderer/renderer_scheduler.h"
 #include "components/scheduler/scheduler_export.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace scheduler {
 
 class SCHEDULER_EXPORT UserModel {
  public:
-  UserModel();
+  UserModel(const scoped_refptr<base::SingleThreadTaskRunner>& task_runner);

[alex clarke (OOO till 29th), 2016/02/12 16:21:50]

nit: explicit and s/task_runner/default_task_runner

[beaudoin, 2016/03/16 20:47:39]

Done.

   ~UserModel();
 
   // Tells us that the system started processing an input event. Must be paired
   // with a call to DidFinishProcessingInputEvent.
   void DidStartProcessingInputEvent(blink::WebInputEvent::Type type,
                                     const base::TimeTicks now);
 
   // Tells us that the system finished processing an input event.
   void DidFinishProcessingInputEvent(const base::TimeTicks now);
 
@@ skipping 30 matching lines @@
   static const int kExpectSubsequentGestureMillis = 2000;
 
   // Clears input signals.
   void Reset(base::TimeTicks now);
 
  private:
   bool IsGestureExpectedSoonImpl(
       const base::TimeTicks now,
       base::TimeDelta* prediction_valid_duration) const;
 
+  // Task runner used to execute tasks on the main thread.
+  scoped_refptr<base::SingleThreadTaskRunner> default_task_runner_;
+
   int pending_input_event_count_;
   base::TimeTicks last_input_signal_time_;
   base::TimeTicks last_gesture_start_time_;
   base::TimeTicks last_continuous_gesture_time_;  // Doesn't include Taps.
   base::TimeTicks last_gesture_expected_start_time_;
   base::TimeTicks last_reset_time_;
   bool is_gesture_active_;  // This typically means the user's finger is down.
   bool is_gesture_expected_;
 
   DISALLOW_COPY_AND_ASSIGN(UserModel);
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_RENDERER_USER_MODEL_H_