MD Settings: Add helper method for responding to cr.sendWithPromise.

chrome/browser/ui/webui/settings/md_settings_ui.cc

Index: chrome/browser/ui/webui/settings/md_settings_ui.cc
diff --git a/chrome/browser/ui/webui/settings/md_settings_ui.cc b/chrome/browser/ui/webui/settings/md_settings_ui.cc
index 3ace24271cc641730b1a45f6bbbeb84d7a7e7474..0db61f479b32615199be0bcec376acb875e92bdf 100644
--- a/chrome/browser/ui/webui/settings/md_settings_ui.cc
+++ b/chrome/browser/ui/webui/settings/md_settings_ui.cc
@@ -40,6 +40,12 @@ SettingsPageUIHandler::SettingsPageUIHandler() {
 SettingsPageUIHandler::~SettingsPageUIHandler() {
 }
 
+void SettingsPageUIHandler::CallJavascriptCallback(
+    const base::Value& callback_id, const base::Value& response) {
+  // cr.webUIResponse is a global JS function exposed from cr.js.
+  web_ui()->CallJavascriptFunction("cr.webUIResponse", callback_id, response);
+}
+
 MdSettingsUI::MdSettingsUI(content::WebUI* web_ui)
     : content::WebUIController(web_ui) {
   Profile* profile = Profile::FromWebUI(web_ui);