Bring up the Fast User Switcher on Shift+Click on the new Avatar Button

chrome/browser/profiles/profile_window.cc

 // Copyright 2013 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/profiles/profile_window.h"
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 490 matching lines @@
       *bubble_view_mode = BUBBLE_VIEW_MODE_GAIA_REAUTH;
       return;
     case BrowserWindow::AVATAR_BUBBLE_MODE_CONFIRM_SIGNIN:
       *bubble_view_mode = BUBBLE_VIEW_MODE_PROFILE_CHOOSER;
       *tutorial_mode = TUTORIAL_MODE_CONFIRM_SIGNIN;
       return;
     case BrowserWindow::AVATAR_BUBBLE_MODE_SHOW_ERROR:
       *bubble_view_mode = BUBBLE_VIEW_MODE_PROFILE_CHOOSER;
       *tutorial_mode = TUTORIAL_MODE_SHOW_ERROR;
       return;
+    case BrowserWindow::AVATAR_BUBBLE_MODE_FAST_USER_SWITCH:
+      if (switches::IsFastUserSwitching())
+        *bubble_view_mode = profiles::BUBBLE_VIEW_MODE_FAST_PROFILE_CHOOSER;
+      else
+        *bubble_view_mode = profiles::BUBBLE_VIEW_MODE_PROFILE_CHOOSER;
+      return;
     default:
       *bubble_view_mode = profiles::BUBBLE_VIEW_MODE_PROFILE_CHOOSER;
   }
 }
 
 }  // namespace profiles