Bug 1761938 - Part 4: Give module loaders a global object field r=smaug,yulia

This gives the module loader a field for the current global, since a module map
is only associated with a single global.

This adds a method to Document to tell the script loader when its global
changes. I'm not sure of when we do this exactly.

Differential Revision: https://phabricator.services.mozilla.com/D142831

js/loader/ModuleLoaderBase.cpp

@@ -52,7 +52,7 @@ NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ModuleLoaderBase)
 NS_INTERFACE_MAP_END
 
 NS_IMPL_CYCLE_COLLECTION(ModuleLoaderBase, mFetchedModules,
-                         mDynamicImportRequests, mLoader)
+                         mDynamicImportRequests, mGlobalObject, mLoader)
 
 NS_IMPL_CYCLE_COLLECTING_ADDREF(ModuleLoaderBase)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(ModuleLoaderBase)
@@ -255,6 +255,8 @@ ModuleLoaderBase* ModuleLoaderBase::GetCurrentModuleLoader(JSContext* aCx) {
     return nullptr;
   }
 
+  MOZ_ASSERT(loader->mGlobalObject == global);
+
   reportError.release();
   return loader;
 }
@@ -461,6 +463,8 @@ nsresult ModuleLoaderBase::CreateModuleScript(ModuleLoadRequest* aRequest) {
     return NS_ERROR_FAILURE;
   }
 
+  MOZ_ASSERT(globalObject == mGlobalObject);
+
   AutoJSAPI jsapi;
   if (!jsapi.Init(globalObject)) {
     return NS_ERROR_FAILURE;
@@ -832,8 +836,12 @@ void ModuleLoaderBase::FinishDynamicImport(
   aRequest->ClearDynamicImport();
 }
 
-ModuleLoaderBase::ModuleLoaderBase(ScriptLoaderInterface* aLoader)
-    : mLoader(aLoader) {
+ModuleLoaderBase::ModuleLoaderBase(ScriptLoaderInterface* aLoader,
+                                   nsIGlobalObject* aGlobalObject)
+    : mGlobalObject(aGlobalObject), mLoader(aLoader) {
+  MOZ_ASSERT(mGlobalObject);
+  MOZ_ASSERT(mLoader);
+
   EnsureModuleHooksInitialized();
 }
 
@@ -992,6 +1000,7 @@ void ModuleLoaderBase::ProcessDynamicImport(ModuleLoadRequest* aRequest) {
 nsresult ModuleLoaderBase::EvaluateModule(nsIGlobalObject* aGlobalObject,
                                           ModuleLoadRequest* aRequest) {
   MOZ_ASSERT(aRequest->mLoader == this);
+  MOZ_ASSERT(aGlobalObject == mGlobalObject);
 
   AUTO_PROFILER_LABEL("ModuleLoaderBase::EvaluateModule", JS);