Support GestureBegin and GestureEnd in ui::GestureProvider

ui/events/gesture_detection/gesture_provider.h

Index: ui/events/gesture_detection/gesture_provider.h
diff --git a/ui/events/gesture_detection/gesture_provider.h b/ui/events/gesture_detection/gesture_provider.h
index fce59268f688c98bf7455069340a5fb9af1830f2..e8bd52d48a2ec2291e1ce2c6367bcabe95858a8a 100644
--- a/ui/events/gesture_detection/gesture_provider.h
+++ b/ui/events/gesture_detection/gesture_provider.h
@@ -32,7 +32,17 @@ class GESTURE_DETECTION_EXPORT GestureProvider {
     GestureDetector::Config gesture_detector_config;
     ScaleGestureDetector::Config scale_gesture_detector_config;
     SnapScrollController::Config snap_scroll_controller_config;
+
+    // There is normally a delay before a tap event is fired, in order to allow

[jdduke (slow), 2014/04/04 19:08:36]

Nit: |When double-tap support is enabled, there will always be a delay before a
tap event is fired...|.

[tdresser, 2014/04/07 13:42:55]

Done.

+    // the double tap gesture to occur without firing any tap events. If
+    // |disable_click_delay| is true, there will be no delay before a tap event
+    // is fired.
     bool disable_click_delay;
+
+    // If |gesture_begin_end_types_enabled| is true, fire an ET_GESTURE_BEGIN
+    // event for every added touch point, and an ET_GESTURE_END event for every
+    // removed touch point.
+    bool gesture_begin_end_types_enabled;
   };
 
   GestureProvider(const Config& config, GestureProviderClient* client);
@@ -97,6 +107,9 @@ class GESTURE_DETECTION_EXPORT GestureProvider {
   bool SendLongTapIfNecessary(const MotionEvent& event);
   void EndTouchScrollIfNecessary(base::TimeTicks time,
                                  bool send_scroll_end_event);
+  void OnTouchEventHandlingBegin(const MotionEvent& event);
+  void OnTouchEventHandlingEnd(const MotionEvent& event);
+
   void UpdateDoubleTapDetectionSupport();
 
   GestureProviderClient* const client_;
@@ -133,6 +146,8 @@ class GESTURE_DETECTION_EXPORT GestureProvider {
   // opened after a GESTURE_LONG_PRESS, this is used to insert a
   // GESTURE_TAP_CANCEL for removing any ::active styling.
   base::TimeTicks current_longpress_time_;
+
+  bool gesture_begin_end_types_enabled_;
 };
 
 }  //  namespace ui