Move {Resolve|Reject}JavascriptCallback helpers in WebUIMessageHandler.

chrome/browser/ui/webui/signin/signin_supervised_user_import_handler.cc

Index: chrome/browser/ui/webui/signin/signin_supervised_user_import_handler.cc
diff --git a/chrome/browser/ui/webui/signin/signin_supervised_user_import_handler.cc b/chrome/browser/ui/webui/signin/signin_supervised_user_import_handler.cc
index c7eb3a4b86be19be15d3b03f3d046d840202b12c..328fce83974df38d382dbdb9550c7750c9471c56 100644
--- a/chrome/browser/ui/webui/signin/signin_supervised_user_import_handler.cc
+++ b/chrome/browser/ui/webui/signin/signin_supervised_user_import_handler.cc
@@ -133,6 +133,7 @@ void SigninSupervisedUserImportHandler::GetExistingSupervisedUsers(
                                      &custodian_profile_path);
   DCHECK(success);
 
+  AllowJavascript();
   // Load custodian profile.
   g_browser_process->profile_manager()->CreateProfileAsync(
       custodian_profile_path,
@@ -190,9 +191,8 @@ void SigninSupervisedUserImportHandler::LoadCustodianProfileCallback(
 
 void SigninSupervisedUserImportHandler::RejectCallback(
     const base::string16& error) {
-  web_ui()->CallJavascriptFunction("cr.webUIResponse",
+  RejectJavascriptCallback(
       base::StringValue(webui_callback_id_),
-      base::FundamentalValue(false),
       base::StringValue(error));
   webui_callback_id_.clear();
 }
@@ -267,9 +267,8 @@ void SigninSupervisedUserImportHandler::SendExistingSupervisedUsers(
   }
 
   // Resolve callback with response.
-  web_ui()->CallJavascriptFunction("cr.webUIResponse",
+  ResolveJavascriptCallback(
       base::StringValue(webui_callback_id_),
-      base::FundamentalValue(true),
       supervised_users);
   webui_callback_id_.clear();
 }