Make EventHandler::ActiveIntervalTimer mockable.

Source/core/page/EventHandler.h

Index: Source/core/page/EventHandler.h
diff --git a/Source/core/page/EventHandler.h b/Source/core/page/EventHandler.h
index 0de3be6c7595b8bc18294b4ddd5ca65bfb6feecb..ff8bc6ad7f1f065fa1c33aa72583a0a605df958b 100755
--- a/Source/core/page/EventHandler.h
+++ b/Source/core/page/EventHandler.h
@@ -149,6 +149,8 @@ public:
     bool bestContextMenuNodeForTouchPoint(const IntPoint& touchCenter, const IntSize& touchRadius, IntPoint& targetPoint, Node*& targetNode);
     bool bestZoomableAreaForTouchPoint(const IntPoint& touchCenter, const IntSize& touchRadius, IntRect& targetArea, Node*& targetNode);
 
+    MockableTimer<EventHandler>* activeIntervalTimerForTesting();
+
     bool adjustGesturePosition(const PlatformGestureEvent&, IntPoint& adjustedPoint);
 
     bool sendContextMenuEvent(const PlatformMouseEvent&);
@@ -392,7 +394,7 @@ private:
     OwnPtr<IntPoint> m_lastSyntheticPanLocation;
     float m_syntheticPageScaleFactor;
 
-    Timer<EventHandler> m_activeIntervalTimer;
+    MockableTimer<EventHandler> m_activeIntervalTimer;
     double m_lastShowPressTimestamp;
     RefPtr<Element> m_lastDeferredTapElement;
 };