Fix TAP_DOWN gesture event:

ui/views/widget/widget.cc

Index: ui/views/widget/widget.cc
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index 7626e96f9bda41ecbecc82ef80b72142cdcc64cd..223137802b7702ced65816c0902af55bbbf11d7c 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -1116,9 +1116,11 @@ ui::GestureStatus Widget::OnGestureEvent(const GestureEvent& event) {
       // dragging) may explicitly capture.
       break;
 
-    case ui::ET_GESTURE_TAP_UP:
-      is_touch_down_ = false;
-      ReleaseCapture();
+    case ui::ET_GESTURE_END:
+      if (event.delta_x() == 1) {

[sky, 2012/06/07 02:43:54]

I don't understand the delta_x check? Why wouldn't we do this all the time?

[sadrul, 2012/06/07 03:04:55]

delta_x() means the number of active points for GESTURE_END. So if you have
three fingers down, releasing one of the fingers will generate a GESTURE_END
with delta_x() == 3. So GESTURE_END with delta_x() == 1 would imply that there
is currently no touch-down (and delta_x() > 1 implies at least some touch-point
is active)

(Naming this delta_x/delta_y is a bit unfortunate, and done for historical
reasons (to match with WebKit). These are planned to be fixed, eventually).

+        is_touch_down_ = false;
+        ReleaseCapture();
+      }
       break;
 
     default: