Support tap_count in ui::GestureProvider.

ui/events/gesture_detection/gesture_detector.h

Index: ui/events/gesture_detection/gesture_detector.h
diff --git a/ui/events/gesture_detection/gesture_detector.h b/ui/events/gesture_detection/gesture_detector.h
index 7552733ec06fe34345e50c09ff3d449e2bd6759b..cbf5921ffaed3ef7e550f0bba16c6ee57ee298df 100644
--- a/ui/events/gesture_detection/gesture_detector.h
+++ b/ui/events/gesture_detection/gesture_detector.h
@@ -69,7 +69,7 @@ class GestureDetector {
     virtual ~GestureListener() {}
     virtual bool OnDown(const MotionEvent& e) = 0;
     virtual void OnShowPress(const MotionEvent& e) = 0;
-    virtual bool OnSingleTapUp(const MotionEvent& e) = 0;
+    virtual bool OnSingleTapUp(const MotionEvent& e, int tap_count) = 0;
     virtual bool OnLongPress(const MotionEvent& e) = 0;
     virtual bool OnScroll(const MotionEvent& e1,
                           const MotionEvent& e2,
@@ -91,7 +91,7 @@ class GestureDetector {
   class DoubleTapListener {
    public:
     virtual ~DoubleTapListener() {}
-    virtual bool OnSingleTapConfirmed(const MotionEvent& e) = 0;
+    virtual bool OnSingleTapConfirmed(const MotionEvent& e, int tap_count) = 0;
     virtual bool OnDoubleTap(const MotionEvent& e) = 0;
     virtual bool OnDoubleTapEvent(const MotionEvent& e) = 0;
   };
@@ -106,7 +106,7 @@ class GestureDetector {
     // GestureListener implementation.
     virtual bool OnDown(const MotionEvent& e) OVERRIDE;
     virtual void OnShowPress(const MotionEvent& e) OVERRIDE;
-    virtual bool OnSingleTapUp(const MotionEvent& e) OVERRIDE;
+    virtual bool OnSingleTapUp(const MotionEvent& e, int tap_count) OVERRIDE;
     virtual bool OnLongPress(const MotionEvent& e) OVERRIDE;
     virtual bool OnScroll(const MotionEvent& e1,
                           const MotionEvent& e2,
@@ -124,7 +124,8 @@ class GestureDetector {
                                 const MotionEvent& e2) OVERRIDE;
 
     // DoubleTapListener implementation.
-    virtual bool OnSingleTapConfirmed(const MotionEvent& e) OVERRIDE;
+    virtual bool OnSingleTapConfirmed(const MotionEvent& e,
+                                      int tap_count) OVERRIDE;
     virtual bool OnDoubleTap(const MotionEvent& e) OVERRIDE;
     virtual bool OnDoubleTapEvent(const MotionEvent& e) OVERRIDE;
   };
@@ -182,6 +183,7 @@ class GestureDetector {
   bool two_finger_tap_allowed_for_gesture_;
 
   scoped_ptr<MotionEvent> current_down_event_;
+  scoped_ptr<MotionEvent> previous_down_event_;
   scoped_ptr<MotionEvent> previous_up_event_;
   scoped_ptr<MotionEvent> secondary_pointer_down_event_;
 
@@ -198,6 +200,10 @@ class GestureDetector {
   bool swipe_enabled_;
   bool two_finger_tap_enabled_;
 
+  // If the double tap gesture is disabled, this counts the number of successive
+  // taps which occured within the double tap window. The current maximum is 3.
+  int tap_count_;
+
   // Determines speed during touch scrolling.
   VelocityTrackerState velocity_tracker_;