Move {Resolve|Reject}JavascriptCallback helpers in WebUIMessageHandler.

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

Index: chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
diff --git a/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc b/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
index 96996852fbda75502929b68b60a7945fa56900b0..c197684907e949e2b71d0a8f7810447753f1fecd 100644
--- a/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
+++ b/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
@@ -502,10 +502,9 @@ void UserManagerScreenHandler::HandleAreAllProfilesLocked(
   bool success = args->GetString(0, &webui_callback_id);
   DCHECK(success);
 
-  web_ui()->CallJavascriptFunction(
-      "cr.webUIResponse",
+  AllowJavascript();
+  ResolveJavascriptCallback(
       base::StringValue(webui_callback_id),
-      base::FundamentalValue(true),
       base::FundamentalValue(profiles::AreAllProfilesLocked()));
 }