Update event states in Env when target window has been destroyed.

ui/aura/env_input_state_controller.cc

 // Copyright 2016 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/env_input_state_controller.h"
 
 #include "ui/aura/client/screen_position_client.h"
 #include "ui/aura/env.h"
 #include "ui/events/event.h"
 #include "ui/gfx/geometry/point.h"
@@ skipping 45 matching lines @@
 
     default:
       NOTREACHED();
       break;
   }
 }
 
 void EnvInputStateController::SetLastMouseLocation(
     const Window* root_window,
     const gfx::Point& location_in_root) const {
+  // If |root_window| is null, we are only using the event to update event
+  // states, so we shouldn't update mouse location.
+  if (!root_window && Env::GetInstance()->mode() == aura::Env::Mode::MUS)
+    return;
+
   client::ScreenPositionClient* client =
       client::GetScreenPositionClient(root_window);
   if (client) {
     gfx::Point location_in_screen = location_in_root;
     client->ConvertPointToScreen(root_window, &location_in_screen);
     Env::GetInstance()->set_last_mouse_location(location_in_screen);
   } else {
     Env::GetInstance()->set_last_mouse_location(location_in_root);
   }
 }
 
 }  // namespace aura