Focus <webview> when Signin focused

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 3f082da765cabb043dff48d56766e0e7795b47e2..6492781c36c103aac1675b5e131f054451d7a216 100644
--- a/chrome/browser/resources/gaia_auth_host/authenticator.js
+++ b/chrome/browser/resources/gaia_auth_host/authenticator.js
@@ -129,6 +129,8 @@ cr.define('cr.login', function() {
     window.addEventListener(
         'message', this.onMessageFromWebview_.bind(this), false);
     window.addEventListener(
+        'focus', this.onFocus_.bind(this), false);
+    window.addEventListener(
         'popstate', this.onPopState_.bind(this), false);
 
     this.loaded_ = false;
@@ -213,6 +215,15 @@ cr.define('cr.login', function() {
   };
 
   /**
+   * Invoked when the sign-in page takes focus.
+   * @param {object} e The focus event being triggered.
+   * @private
+   */
+  Authenticator.prototype.onFocus_ = function(e) {
+    this.webview_.focus();
+  };
+
+  /**
    * Invoked when the history state is changed.
    * @param {object} e The popstate event being triggered.
    * @private