MD User Manager: Display error message when all profiles are locked.

chrome/browser/resources/md_user_manager/control_bar.js

Index: chrome/browser/resources/md_user_manager/control_bar.js
diff --git a/chrome/browser/resources/md_user_manager/control_bar.js b/chrome/browser/resources/md_user_manager/control_bar.js
index 3c2b6362923985860b326cf118c8863693892a23..0e2fd89a0c6de96129f9763181aef0c83bcd3905 100644
--- a/chrome/browser/resources/md_user_manager/control_bar.js
+++ b/chrome/browser/resources/md_user_manager/control_bar.js
@@ -9,6 +9,10 @@
  Polymer({
   is: 'control-bar',
 
+  behaviors: [
+    I18nBehavior,
+  ],
+
   properties: {
     /**
      * True if 'Browse as Guest' button is displayed.
@@ -43,7 +47,15 @@
    * @private
    */
   onLaunchGuestTap_: function(event) {
-    this.browserProxy_.launchGuestUser();
+    this.browserProxy_.isAtLeastOneProfileUnlocked().then(
+        function() {
+          this.browserProxy_.launchGuestUser();
+        }.bind(this),
+        function() {
+          cr.webUIListenerCallback(
+              'show-error-dialog',
+              this.i18n('BrowseAsGuestAllProfilesLockedError'));
+        }.bind(this));
   },
 
   /**
@@ -52,7 +64,15 @@
    * @private
    */
   onAddUserTap_: function(event) {
-    // Event is caught by user-manager-pages.
-    this.fire('change-page', {page: 'create-user-page'});
+    this.browserProxy_.isAtLeastOneProfileUnlocked().then(
+        function() {
+          // Event is caught by user-manager-pages.
+          this.fire('change-page', {page: 'create-user-page'});
+        }.bind(this),
+        function() {
+          cr.webUIListenerCallback(
+              'show-error-dialog',
+              this.i18n('AddProfileAllProfilesLockedError'));
+        }.bind(this));
   }
 });