[cros,login] Restore the focus after hidden auth extension has grabbed it.

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

Index: chrome/browser/resources/chromeos/login/screen_gaia_signin.js
diff --git a/chrome/browser/resources/chromeos/login/screen_gaia_signin.js b/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
index 7dbfb055c7ce8cd2f4a70ddc5efcaac8f63bbb94..0d524abea8993f4a263c33a64521704b4891ad32 100644
--- a/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
+++ b/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
@@ -30,7 +30,13 @@ cr.define('login', function() {
     __proto__: HTMLDivElement.prototype,
 
     // Authentication extension's start page URL.
-    extension_url_: null,
+    extensionUrl_: null,
+
+    // Whether extension should be loaded silently.
+    silentLoad_: false,
+
+    // Whether there is focused element.
+    hasFocused_: false,
 
     // Number of times that we reload extension frame.
     retryCount_: 0,
@@ -40,6 +46,8 @@ cr.define('login', function() {
 
     /** @inheritDoc */
     decorate: function() {
+      this.frame_ = $('signin-frame');
+
       $('createAccount').innerHTML = localStrings.getStringF(
           'createAccount',
           '<a id="createAccountLink" class="signin-link" href="#">',
@@ -54,6 +62,8 @@ cr.define('login', function() {
       $('guestSigninLink').onclick = function() {
         chrome.send('launchIncognito');
       };
+      document.addEventListener(
+          'focusin', this.selfBind_(this.onFocusIn_.bind(this)));
     },
 
     /**
@@ -71,7 +81,7 @@ cr.define('login', function() {
      */
     showLoadingUI_: function(show) {
       $('gaia-loading').hidden = !show;
-      $('signin-frame').hidden = show;
+      this.frame_.hidden = show;
 
       // Sign-in right panel is hidden if all its items are hidden.
       $('signin-right').hidden = show ||
@@ -107,7 +117,42 @@ cr.define('login', function() {
       Oobe.getInstance().headerHidden = false;
     },
 
-    setExtensionUrl_: function(data) {
+    /**
+     * Returns function which gets an event and passes it and self to listener.
+     * @param {!Object} listener Listener to be wrapped.
+     */
+    selfBind_: function(listener) {
+      var selfBinded = function(e) {
+        listener(e, selfBinded);
+      }
+      return selfBinded;
+    },
+
+    /**
+     * Tracks first focus in event.
+     * @param {!Object} e Focus in event.
+     * @param {!Object} listener Listener which shold be removed from event
+     *   listeners list.
+     */
+    onFocusIn_: function(e, listener) {
+      this.hasFocused_ = true;
+      document.removeEventListener('focusin', listener);
+    },
+
+    /**
+     * Restore focus back to the focused element.
+     * @param {!Object} e Focus out event.
+     * @param {!Object} listener Listener which shold be removed from event
+     *   listeners list.
+     */
+    onFocusOut_: function(e, listener) {
+      window.setTimeout(e.target.focus.bind(e.target), 0);
+      document.removeEventListener('focusout', listener);
+    },
+
+    loadAuthExtension_: function(data) {
+      this.silentLoad_ = data.silentLoad;
+
       $('createAccount').hidden = !data.createAccount;
       $('guestSignin').hidden = !data.guestSignin;
 
@@ -127,12 +172,12 @@ cr.define('login', function() {
       if (params.length)
         url += '?' + params.join('&');
 
-      if (data.forceReload || this.extension_url_ != url) {
+      if (data.forceReload || this.extensionUrl_ != url) {
         console.log('Opening extension: ' + data.startUrl +
                     ', opt_email=' + data.email);
 
-        $('signin-frame').src = url;
-        this.extension_url_ = url;
+        this.frame_.src = url;
+        this.extensionUrl_ = url;
 
         this.loading = true;
         this.clearRetry_();
@@ -148,9 +193,9 @@ cr.define('login', function() {
      * @type {bool}
      */
     isAuthExtMessage_: function(e) {
-      return this.extension_url_ != null &&
-          this.extension_url_.indexOf(e.origin) == 0 &&
-          e.source == $('signin-frame').contentWindow;
+      return this.extensionUrl_ != null &&
+          this.extensionUrl_.indexOf(e.origin) == 0 &&
+          e.source == this.frame_.contentWindow;
     },
 
     /**
@@ -165,6 +210,13 @@ cr.define('login', function() {
         // Now that we're in logged in state header should be hidden.
         Oobe.getInstance().headerHidden = true;
       } else if (msg.method == 'loginUILoaded' && this.isAuthExtMessage_(e)) {
+        // TODO(altimofeev): there is no guarantee that next 'focusout' event
+        // will be caused by the extension, so better approach is direct asking
+        // the extension (and gaia consequently) to not grab the focus.
+        if (this.silentLoad_ && this.hasFocused_) {
+          document.addEventListener(
+              'focusout', this.selfBind_(this.onFocusOut_.bind(this)));
+        }
         $('error-message').update();
         this.loading = false;
         this.clearRetry_();
@@ -199,7 +251,7 @@ cr.define('login', function() {
      */
     doReload: function() {
       console.log('Reload auth extension frame.');
-      $('signin-frame').src = this.extension_url_;
+      this.frame_.src = this.extensionUrl_;
       this.retryTimer_ = undefined;
     },
 
@@ -222,8 +274,8 @@ cr.define('login', function() {
     }
   };
 
-  GaiaSigninScreen.setExtensionUrl = function(data) {
-    $('gaia-signin').setExtensionUrl_(data);
+  GaiaSigninScreen.loadAuthExtension = function(data) {
+    $('gaia-signin').loadAuthExtension_(data);
   };
 
   return {