Bug 1510817 - Don't doubly warn when we can't load a script due to tracking protection; r=baku

Differential Revision: https://phabricator.services.mozilla.com/D14861

dom/script/ScriptLoader.cpp

@@ -2919,6 +2919,9 @@ void ScriptLoader::ReportErrorToConsole(ScriptLoadRequest* aRequest,
     message = isScript ? "ScriptSourceMalformed" : "ModuleSourceMalformed";
   } else if (aResult == NS_ERROR_DOM_BAD_URI) {
     message = isScript ? "ScriptSourceNotAllowed" : "ModuleSourceNotAllowed";
+  } else if (aResult == NS_ERROR_TRACKING_URI) {
+    // Tracking protection errors already show their own console messages.
+    return;
   } else {
     message = isScript ? "ScriptSourceLoadFailed" : "ModuleSourceLoadFailed";
   }