Fixed header bar UI behaviour.

chrome/browser/resources/chromeos/login/screen_account_picker.js

 // 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.
 
 /**
  * @fileoverview Account picker screen implementation.
  */
 
 cr.define('login', function() {
   /**
@@ skipping 57 matching lines @@
     onAfterShow: function(data) {
       $('pod-row').handleAfterShow();
     },
 
     /**
      * Event handler that is invoked just before the frame is shown.
      * @param {string} data Screen init payload.
      */
     onBeforeShow: function(data) {
       chrome.send('loginUIStateChanged', ['account-picker', true]);
+      $('login-header-bar').signinUIState = SIGNIN_UI_STATE.ACCOUNT_PICKER;
       chrome.send('hideCaptivePortal');
       var podRow = $('pod-row');
       podRow.handleBeforeShow();
 
       // If this is showing for the lock screen display the sign out button,
       // hide the add user button and activate the locked user's pod.
       var lockedPod = podRow.lockedPod;
       $('add-user-header-bar-item').hidden = !!lockedPod;
       $('sign-out-user-item').hidden = !lockedPod;
       // In case of the preselected pod onShow will be called once pod
@@ skipping 14 matching lines @@
 
       chrome.send('accountPickerReady');
       chrome.send('loginVisible', ['account-picker']);
     },
 
     /**
      * Event handler that is invoked just before the frame is hidden.
      */
     onBeforeHide: function() {
       chrome.send('loginUIStateChanged', ['account-picker', false]);
+      $('login-header-bar').signinUIState = SIGNIN_UI_STATE.HIDDEN;
       $('pod-row').handleHide();
     },
 
     /**
      * Shows sign-in error bubble.
      * @param {number} loginAttempts Number of login attemps tried.
      * @param {HTMLElement} content Content to show in bubble.
      */
     showErrorBubble: function(loginAttempts, error) {
       var activatedPod = $('pod-row').activatedPod;
@@ skipping 91 matching lines @@
     };
     // Start image loading.
     // Add timestamp for wallpapers that are rotated over time.
     image.src = 'chrome://wallpaper/' + new Date().getTime();
   };
 
   return {
     AccountPickerScreen: AccountPickerScreen
   };
 });