Support tap_count in ui::GestureProvider.

ui/events/gestures/gesture_provider_aura.h

Index: ui/events/gestures/gesture_provider_aura.h
diff --git a/ui/events/gestures/gesture_provider_aura.h b/ui/events/gestures/gesture_provider_aura.h
index b4a9dedf3a37d3359d5f43d0d32addd92ed32461..5722be6a261565258226d797c31b977e2ad63a8d 100644
--- a/ui/events/gestures/gesture_provider_aura.h
+++ b/ui/events/gestures/gesture_provider_aura.h
@@ -36,6 +36,11 @@ class EVENTS_EXPORT GestureProviderAura : public GestureProviderClient {
   virtual void OnGestureEvent(const GestureEventData& gesture) OVERRIDE;
 
  private:
+  bool IsConsideredDoubleTap(const GestureEventData& previous_tap,
+                             const GestureEventData& current_tap) const;
+
+  scoped_ptr<GestureEventData> previous_tap_;
+
   GestureProviderAuraClient* client_;
   MotionEventAura pointer_state_;
   FilteredGestureProvider filtered_gesture_provider_;