Ensure Multi-finger tap generates both GestureScrollBegin and GestureScrollEnd.

ui/events/gestures/gesture_sequence.cc

 // Copyright (c) 2012 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.
 
 #include "ui/events/gestures/gesture_sequence.h"
 
 #include <stdlib.h>
 #include <cmath>
 #include <limits>
 
@@ skipping 615 matching lines @@
     case GST_SYNTHETIC_CLICK_ABORTED_SECOND_PRESSED:
       TwoFingerTapOrPinch(event, point, gestures.get());
       break;
     case GST_SCROLL_SECOND_PRESSED:
       PinchStart(event, point, gestures.get());
       set_state(GS_PINCH);
       break;
     case GST_PENDING_TWO_FINGER_TAP_FIRST_RELEASED:
     case GST_PENDING_TWO_FINGER_TAP_SECOND_RELEASED:
       TwoFingerTouchReleased(event, point, gestures.get());
+      AppendScrollGestureBegin(
+          point, point.first_touch_position(), gestures.get());
+      scroll_type_ = ST_FREE;
       set_state(GS_SCROLL);
       break;
     case GST_PENDING_TWO_FINGER_TAP_FIRST_MOVED:
     case GST_PENDING_TWO_FINGER_TAP_SECOND_MOVED:
       if (TwoFingerTouchMove(event, point, gestures.get()))
         set_state(GS_PINCH);
       break;
     case GST_PENDING_TWO_FINGER_TAP_FIRST_MOVED_HANDLED:
     case GST_PENDING_TWO_FINGER_TAP_SECOND_MOVED_HANDLED:
       set_state(GS_PENDING_TWO_FINGER_TAP_NO_PINCH);
       break;
     case GST_PENDING_TWO_FINGER_TAP_FIRST_RELEASED_HANDLED:
     case GST_PENDING_TWO_FINGER_TAP_SECOND_RELEASED_HANDLED:
     case GST_PENDING_TWO_FINGER_TAP_FIRST_CANCELLED:
     case GST_PENDING_TWO_FINGER_TAP_SECOND_CANCELLED:
       scroll_type_ = ST_FREE;
       set_state(GS_SCROLL);

[sadrul, 2014/03/07 18:07:07]

Do you need the same change here, and in lines ~669, ~678, ~696, ~709?

[tdresser, 2014/03/07 19:23:27]

Absolutely. Done.

       break;
     case GST_PENDING_TWO_FINGER_TAP_THIRD_PRESSED:
       set_state(GS_PENDING_PINCH);
       break;
     case GST_PENDING_TWO_FINGER_TAP_NO_PINCH_FIRST_MOVED:
     case GST_PENDING_TWO_FINGER_TAP_NO_PINCH_SECOND_MOVED:
       // No pinch allowed, so nothing happens.
       break;
     case GST_PENDING_TWO_FINGER_TAP_NO_PINCH_FIRST_RELEASED:
     case GST_PENDING_TWO_FINGER_TAP_NO_PINCH_SECOND_RELEASED:
@@ skipping 810 matching lines @@
 
   // Since a timer is running, there should be a non-NULL point.
   const GesturePoint* point = GetPointByPointId(0);
   if (!point->IsInsideTouchSlopRegion(event)) {
     GetLongPressTimer()->Stop();
     GetShowPressTimer()->Stop();
   }
 }
 
 }  // namespace ui