Added keyboard shortcut on GAIA "Add User" screen to dogfood GAIA /EmbeddedSignin

ui/login/display_manager.js

Index: ui/login/display_manager.js
diff --git a/ui/login/display_manager.js b/ui/login/display_manager.js
index 8f8c60d071020564d3424630d8543b48199ff925..5561b9e2375e257d97432743c5f941ccdbf82f90 100644
--- a/ui/login/display_manager.js
+++ b/ui/login/display_manager.js
@@ -46,6 +46,7 @@
 /** @const */ var ACCELERATOR_APP_LAUNCH_BAILOUT = 'app_launch_bailout';
 /** @const */ var ACCELERATOR_APP_LAUNCH_NETWORK_CONFIG =
     'app_launch_network_config';
+/** @const */ var ACCELERATOR_EMBEDDED_SIGNIN = 'embedded_signin';
 
 /* Signin UI state constants. Used to control header bar UI. */
 /** @const */ var SIGNIN_UI_STATE = {
@@ -374,6 +375,9 @@ cr.define('cr.ui.login', function() {
       } else if (name == ACCELERATOR_APP_LAUNCH_NETWORK_CONFIG) {
         if (currentStepId == SCREEN_APP_LAUNCH_SPLASH)
           chrome.send('networkConfigRequest');
+      } else if (name == ACCELERATOR_EMBEDDED_SIGNIN) {
+        if (currentStepId == SCREEN_GAIA_SIGNIN)
+          chrome.send('switchToEmbeddedSignin');
       }
 
       if (!this.forceKeyboardFlow_)