Remove unused code from test methods

[ Merge from http://go/wvgerrit/16406 ]

This was detected by static analysis tool cppcheck.

b/26348775

Change-Id: Icc6a55b9b4a1ffe882488ac069e3c3df2e796e91

libwvdrmengine/cdm/test/timer_unittest.cpp

@@ -13,7 +13,6 @@ class TestTimerHandler : public TimerHandler {
   virtual void OnTimerEvent() { timer_events_++; }
 
   uint32_t timer_events() { return timer_events_; }
-  void ResetTimerEvents() { timer_events_ = 0; }
 
  private:
   uint32_t timer_events_;