[M-37]: Fix dragging tab via mouse when touch is down on ChromeOS

ash/wm/toplevel_window_event_handler.cc

Index: ash/wm/toplevel_window_event_handler.cc
diff --git a/ash/wm/toplevel_window_event_handler.cc b/ash/wm/toplevel_window_event_handler.cc
index 5d9ce4bb0d409190e5f2bd17fc637ef124d4f2c3..a759e8b76b875aa0ce5465357690d51d7ce0d83c 100644
--- a/ash/wm/toplevel_window_event_handler.cc
+++ b/ash/wm/toplevel_window_event_handler.cc
@@ -494,8 +494,11 @@ void ToplevelWindowEventHandler::HandleMouseReleased(
   if (event->phase() != ui::EP_PRETARGET)
     return;
 
-  CompleteDrag(event->type() == ui::ET_MOUSE_RELEASED ?
-                   DRAG_COMPLETE : DRAG_REVERT);
+  if (window_resizer_) {

[pkotwicz, 2014/06/28 18:37:36]

We should also avoid calling CompleteDrag() here if the drag has already been
completed. I will fix this up as part of another CL.

[varkha, 2014/07/04 23:09:01]

Should this method just return early when !window_resizer_? This would simplify
the logic here and below.

+    CompleteDrag(event->type() == ui::ET_MOUSE_RELEASED ?
+                     DRAG_COMPLETE : DRAG_REVERT);
+  }
+
   // Completing the drag may result in hiding the window. If this happens
   // mark the event as handled so no other handlers/observers act upon the
   // event. They should see the event on a hidden window, to determine targets