Splits ToplevelWindowEventHandler into two

ash/wm/aura/wm_globals_aura.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 "ash/wm/aura/wm_globals_aura.h"
 
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/session/session_state_delegate.h"
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
@@ skipping 148 matching lines @@
 
 void WmGlobalsAura::OnWindowActivated(
     aura::client::ActivationChangeObserver::ActivationReason reason,
     aura::Window* gained_active,
     aura::Window* lost_active) {
   FOR_EACH_OBSERVER(WmActivationObserver, activation_observers_,
                     OnWindowActivated(WmWindowAura::Get(gained_active),
                                       WmWindowAura::Get(lost_active)));
 }
 
+void WmGlobalsAura::OnDisplayConfigurationChanging() {
+  FOR_EACH_OBSERVER(WmDisplayObserver, display_observers_,
+                    OnDisplayConfigurationChanging());
+}
+
 void WmGlobalsAura::OnDisplayConfigurationChanged() {
   FOR_EACH_OBSERVER(WmDisplayObserver, display_observers_,
                     OnDisplayConfigurationChanged());
 }
 
 void WmGlobalsAura::OnOverviewModeEnded() {
   FOR_EACH_OBSERVER(WmOverviewModeObserver, overview_mode_observers_,
                     OnOverviewModeEnded());
 }
 
 }  // namespace wm
 }  // namespace ash