Add window overview mode behind --ash-enable-overview-mode flag to F5 key.

chrome/browser/ui/ash/chrome_shell_delegate.cc

 // Copyright (c) 2012 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 "chrome/browser/ui/ash/chrome_shell_delegate.h"
 
 #include "apps/shell_window.h"
 #include "ash/ash_switches.h"
 #include "ash/host/root_window_host_factory.h"
 #include "ash/launcher/launcher_types.h"
@@ skipping 296 matching lines @@
       break;
     case ash::UMA_ACCEL_NEWTAB_T:
       content::RecordAction(content::UserMetricsAction("Accel_NewTab_T"));
       break;
     case ash::UMA_ACCEL_NEXTWINDOW_F5:
       content::RecordAction(content::UserMetricsAction("Accel_NextWindow_F5"));
       break;
     case ash::UMA_ACCEL_NEXTWINDOW_TAB:
       content::RecordAction(content::UserMetricsAction("Accel_NextWindow_Tab"));
       break;
+    case ash::UMA_ACCEL_OVERVIEW_F5:
+      content::RecordAction(content::UserMetricsAction("Accel_Overview_F5"));
+      break;
     case ash::UMA_ACCEL_PREVWINDOW_F5:
       content::RecordAction(content::UserMetricsAction("Accel_PrevWindow_F5"));
       break;
     case ash::UMA_ACCEL_PREVWINDOW_TAB:
       content::RecordAction(content::UserMetricsAction("Accel_PrevWindow_Tab"));
       break;
     case ash::UMA_ACCEL_EXIT_FIRST_Q:
       content::RecordAction(content::UserMetricsAction("Accel_Exit_First_Q"));
       break;
     case ash::UMA_ACCEL_EXIT_SECOND_Q:
@@ skipping 118 matching lines @@
     return browser;
   return chrome::FindOrCreateTabbedBrowser(
       ProfileManager::GetDefaultProfileOrOffTheRecord(),
       chrome::HOST_DESKTOP_TYPE_ASH);
 }
 
 keyboard::KeyboardControllerProxy*
     ChromeShellDelegate::CreateKeyboardControllerProxy() {
   return new AshKeyboardControllerProxy();
 }