Load webview based GAIA in hidden state and pass focus when ready

chrome/browser/resources/gaia_auth_host/authenticator.js

Index: chrome/browser/resources/gaia_auth_host/authenticator.js
diff --git a/chrome/browser/resources/gaia_auth_host/authenticator.js b/chrome/browser/resources/gaia_auth_host/authenticator.js
index db85d62bb75a08eea9ed94f7238b52e0d3b7a81d..87f9c386141b030847f1b6e221a155830913563b 100644
--- a/chrome/browser/resources/gaia_auth_host/authenticator.js
+++ b/chrome/browser/resources/gaia_auth_host/authenticator.js
@@ -156,23 +156,6 @@ cr.define('cr.login', function() {
     this.loaded_ = false;
   };
 
-  /**
-   * Send message 'focusready' to Gaia so it sets focus on default input.
-   */
-  Authenticator.prototype.sendFocusReady = function() {
-    var currentUrl = this.webview_.src;
-    if (currentUrl.lastIndexOf(this.idpOrigin_) == 0) {
-      var msg = {
-        'method': 'focusready'
-      };
-      // TODO(rsorokin): Get rid of this check once issue crbug.com/456118 is
-      // fixed.
-      if (this.webview_.contentWindow) {
-        this.webview_.contentWindow.postMessage(msg, currentUrl);
-      }
-    }
-  };
-
   Authenticator.prototype.constructInitialFrameUrl_ = function(data) {
     var url = this.idpOrigin_ + (data.gaiaPath || IDP_PATH);
 
@@ -393,8 +376,9 @@ cr.define('cr.login', function() {
   Authenticator.prototype.onLoadStop_ = function(e) {
     if (!this.loaded_) {
       this.loaded_ = true;
-      this.webview_.focus();
       this.dispatchEvent(new Event('ready'));
+      // Focus webview after dispatching event when webview is already visible.
+      this.webview_.focus();
     }
   };