Report user actions when gesture starts and stops in user_model.

components/scheduler/renderer/user_model.h

Index: components/scheduler/renderer/user_model.h
diff --git a/components/scheduler/renderer/user_model.h b/components/scheduler/renderer/user_model.h
index f93b10beadcfa0f2cfbffed5454f3d3e62b2ba35..98664d684778f13e455e3f08d25cf225e6a86b33 100644
--- a/components/scheduler/renderer/user_model.h
+++ b/components/scheduler/renderer/user_model.h
@@ -12,11 +12,15 @@
 #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);
   ~UserModel();
 
   // Tells us that the system started processing an input event. Must be paired
@@ -67,6 +71,9 @@ class SCHEDULER_EXPORT UserModel {
       const base::TimeTicks now,
       base::TimeDelta* prediction_valid_duration) const;
 
+  // Task runner used to execute tasks on the main thread.
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;

[alex clarke (OOO till 29th), 2016/02/10 10:17:01]

s/task_runner_/default_task_runner_

Reason being there are many types of task runner used in the scheduler and it
would be good to know what sort this is when reading the UserModel code.

[beaudoin, 2016/02/11 22:03:27]

Done.

+
   int pending_input_event_count_;
   base::TimeTicks last_input_signal_time_;
   base::TimeTicks last_gesture_start_time_;