Tweak the aura gesture recognizer slightly.

ui/aura/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/aura/gestures/gesture_sequence.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/aura/event.h"
 #include "ui/base/events.h"
@@ skipping 81 matching lines @@
       break;
   }
 
   if (event.type() == ui::ET_TOUCH_RELEASED)
     --point_count_;
 
   return gestures.release();
 }
 
 void GestureSequence::Reset() {
-  state_ = GS_NO_GESTURE;
+  set_state(GS_NO_GESTURE);
   for (int i = 0; i < point_count_; ++i)
     points_[i].Reset();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // GestureSequence Private:
 
 unsigned int GestureSequence::Signature(GestureState gesture_state,
     unsigned int touch_id,
     ui::EventType type,
@@ skipping 76 matching lines @@
       base::Time::FromDoubleT(point.last_touch_time()),
       point.x_delta(), point.y_delta())));
 }
 
 bool GestureSequence::Click(const TouchEvent& event,
     const GesturePoint& point, Gestures* gestures) {
   if (point.IsInClickWindow(event)) {
     AppendClickGestureEvent(point, gestures);
     if (point.IsInDoubleClickWindow(event))
       AppendDoubleClickGestureEvent(point, gestures);
+    set_state(GS_NO_GESTURE);
     return true;
   }
   return false;
 }
 
 bool GestureSequence::InClickOrScroll(const TouchEvent& event,
     const GesturePoint& point, Gestures* gestures) {
   if (point.IsInClickWindow(event)) {
     set_state(GS_PENDING_SYNTHETIC_CLICK);
     return false;
   }
   if (point.IsInScrollWindow(event)) {
     AppendScrollGestureBegin(point, gestures);
     AppendScrollGestureUpdate(point, gestures);
     set_state(GS_SCROLL);
     return true;
   }
   return false;
 }
 
 bool GestureSequence::InScroll(const TouchEvent& event,
     const GesturePoint& point, Gestures* gestures) {
+  if (!point.DidScroll(event))
+    return false;
   AppendScrollGestureUpdate(point, gestures);
   return true;
 }
 
 bool GestureSequence::NoGesture(const TouchEvent&,
     const GesturePoint& point, Gestures*) {
   Reset();
   return false;
 }
 
 bool GestureSequence::TouchDown(const TouchEvent& event,
     const GesturePoint& point, Gestures* gestures) {
   AppendTapDownGestureEvent(point, gestures);
   set_state(GS_PENDING_SYNTHETIC_CLICK);
   return false;
 }
 
 bool GestureSequence::ScrollEnd(const TouchEvent& event,
     const GesturePoint& point, Gestures* gestures) {
   if (point.IsInFlickWindow(event))
     AppendScrollGestureEnd(point, gestures, point.x_velocity(),
         point.y_velocity());
   else
     AppendScrollGestureEnd(point, gestures, 0.f, 0.f);
-  set_state(GS_NO_GESTURE);
   Reset();
   return false;
 }
 
 }  // namespace aura