Refactor Timer classes in preparation for landing FrameTimers.

third_party/WebKit/Source/core/frame/PlatformEventController.h

 // Copyright 2014 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 PlatformEventController_h
 #define PlatformEventController_h
 
 #include "core/CoreExport.h"
 #include "core/page/PageVisibilityObserver.h"
 #include "platform/Timer.h"
@@ skipping 22 matching lines @@
 
     // When true initiates a one-shot didUpdateData() when startUpdating() is called.
     virtual bool hasLastData() = 0;
 
     bool m_hasEventListener;
 
 private:
     // Inherited from PageVisibilityObserver.
     void pageVisibilityChanged() override;
 
-    void oneShotCallback(Timer<PlatformEventController>*);
+    void oneShotCallback(TimerBase*);
 
     bool m_isActive;
     Timer<PlatformEventController> m_timer;
 };
 
 } // namespace blink
 
 #endif // PlatformEventController_h