Fix an interactive ui test

ui/aura/window_event_dispatcher.cc

Index: ui/aura/window_event_dispatcher.cc
diff --git a/ui/aura/window_event_dispatcher.cc b/ui/aura/window_event_dispatcher.cc
index 559c9524748a85e10b0cb0fc40780d28baeb5aef..6dca4671f0cb9701f2e0185cffb3501d06a9e476 100644
--- a/ui/aura/window_event_dispatcher.cc
+++ b/ui/aura/window_event_dispatcher.cc
@@ -309,11 +309,16 @@ ui::EventDispatchDetails WindowEventDispatcher::ProcessGestures(
   if (!target)
     return details;
 
+  WindowEventDispatcher* dispatcher = this;
   for (const auto& event : gestures) {
-    event->ConvertLocationToTarget(window(), target);
-    details = DispatchEvent(target, event.get());
+    event->ConvertLocationToTarget(dispatcher->window(), target);
+    details = dispatcher->DispatchEvent(target, event.get());
     if (details.dispatcher_destroyed || details.target_destroyed)
       break;
+    // If the target window has moved off to a different WindowTreeHost, then
+    // reroute them to the right place.
+    if (!dispatcher->window()->Contains(target))
+      dispatcher = target->GetHost()->dispatcher();

[sadrul, 2017/04/27 02:33:31]

We should no longer need this change. If you want to make a change here, please
add a DCHECK(window()->Contains(target)) instead.

[weidongg, 2017/04/27 03:07:32]

Sure, I could leave this file untouched, as
WindowEventDispatcher::PreDispatchEvent already does the check.

   }
   return details;
 }