[MD settings] disable clear browsing data while it is running

chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_browser_proxy.js

Index: chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_browser_proxy.js
diff --git a/chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_browser_proxy.js b/chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_browser_proxy.js
index d90a81b312c83681dcf5e1be583a28aeceadd521..bb581acd8ec6fffbb95dcb814f6aa9c63513e54b 100644
--- a/chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_browser_proxy.js
+++ b/chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_browser_proxy.js
@@ -17,7 +17,10 @@ cr.define('settings', function() {
      */
     clearBrowsingData: function() {},
 
-    /** Initializes the dialog. */
+    /**
+     * Kick off counter updates and return initial state.
+     * @return {!Promise} Signal when the setup is complete.

[dpapad, 2016/07/08 18:04:42]

initialize() does not seem to return anything in the Promise anymore. Can you
update the comment?
Also it seems that calling initialize triggers a series of WebUI events. Can we
explicitly list them here?

+     */
     initialize: function() {},
   };
 
@@ -36,7 +39,7 @@ cr.define('settings', function() {
 
     /** @override */
     initialize: function() {
-      chrome.send('initializeClearBrowsingData');
+      return cr.sendWithPromise('initializeClearBrowsingData');
     },
   };