Bug 1436400 - Part 9: Support restarting module load request. r=jonco

After enabling bytecode cache for module script, we need to handle
the SRI mismatch on bytecode cache, that requires reloading the script source
again.

Differential Revision: https://phabricator.services.mozilla.com/D140551

js/loader/ModuleLoaderBase.cpp

@@ -113,6 +113,12 @@ bool ModuleLoaderBase::ModuleMapContainsURL(nsIURI* aURL,
   return mFetchingModules.Contains(key) || mFetchedModules.Contains(key);
 }
 
+bool ModuleLoaderBase::IsModuleFetching(nsIURI* aURL,
+                                        nsIGlobalObject* aGlobal) const {
+  ModuleMapKey key(aURL, aGlobal);
+  return mFetchingModules.Contains(key);
+}
+
 void ModuleLoaderBase::SetModuleFetchStarted(ModuleLoadRequest* aRequest) {
   // Update the module map to indicate that a module is currently being fetched.