base: add MockTimer

base/timer/timer.h

Index: base/timer/timer.h
diff --git a/base/timer/timer.h b/base/timer/timer.h
index 71a7ae8888a3afd82be5419b24e4d0df22da2955..8cdd925e5d86bf7f2d1ea976df478cf813dffb3c 100644
--- a/base/timer/timer.h
+++ b/base/timer/timer.h
@@ -82,28 +82,28 @@ class BASE_EXPORT Timer {
   virtual ~Timer();
 
   // Returns true if the timer is running (i.e., not stopped).
-  bool IsRunning() const {
+  virtual bool IsRunning() const {

[Mark Mentovai, 2014/03/13 15:17:34]

Do all of these need to become virtual? What about if we do more sharing of the
fields as I suggested in my comments in mock_timer.h?

[Elly Fong-Jones, 2014/03/13 15:30:09]

I could make is_running_ and delay_ protected, maybe? Otherwise since there are
no setters for them the child class needs to be able to return its own values.

[Mark Mentovai, 2014/03/13 15:48:56]

Elly Jones wrote:
We don’t make data members protected, ever. But you can have protected helper
methods that operate on private data.

It looks like you can get rid of the mock class’ copies of delay_ and user_task_
altogether. Just remove GetCurrentDelay, Start, and Stop. The base class’
implementations are appropriate as-is, and you can remove the “virtual” from
both of those. In Fire(), you can access the base user_task_ via the public
user_task() getter.

is_running_ is a bit trickier. I think that you can share the base class’ copy
of is_running_ if you gave the base a protected method to deal with is_running_.
But it’s probably not worth perverting the base class in this way for just the
mock class, so I’d be inclined to leave it alone.

     return is_running_;
   }
 
   // Returns the current delay for this timer.
-  TimeDelta GetCurrentDelay() const {
+  virtual TimeDelta GetCurrentDelay() const {
     return delay_;
   }
 
   // Start the timer to run at the given |delay| from now. If the timer is
   // already running, it will be replaced to call the given |user_task|.
-  void Start(const tracked_objects::Location& posted_from,
+  virtual void Start(const tracked_objects::Location& posted_from,
              TimeDelta delay,
              const base::Closure& user_task);
 
   // Call this method to stop and cancel the timer.  It is a no-op if the timer
   // is not running.
-  void Stop();
+  virtual void Stop();
 
   // Call this method to reset the timer delay. The user_task_ must be set. If
   // the timer is not running, this will start it by posting a task.
-  void Reset();
+  virtual void Reset();
 
   const base::Closure& user_task() const { return user_task_; }
   const TimeTicks& desired_run_time() const { return desired_run_time_; }
@@ -197,7 +197,7 @@ class BaseTimerMethodPointer : public Timer {
   // Start the timer to run at the given |delay| from now. If the timer is
   // already running, it will be replaced to call a task formed from
   // |reviewer->*method|.
-  void Start(const tracked_objects::Location& posted_from,
+  virtual void Start(const tracked_objects::Location& posted_from,
              TimeDelta delay,
              Receiver* receiver,
              ReceiverMethod method) {