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.h

@@ -92,6 +92,8 @@ class ModuleLoaderBase : public nsISupports {
   // List of dynamic imports that are currently being loaded.
   ScriptLoadRequestList mDynamicImportRequests;
 
+  nsCOMPtr<nsIGlobalObject> mGlobalObject;
+
  protected:
   RefPtr<ScriptLoaderInterface> mLoader;
 
@@ -100,7 +102,8 @@ class ModuleLoaderBase : public nsISupports {
  public:
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_CLASS(ModuleLoaderBase)
-  explicit ModuleLoaderBase(ScriptLoaderInterface* aLoader);
+  explicit ModuleLoaderBase(ScriptLoaderInterface* aLoader,
+                            nsIGlobalObject* aGlobalObject);
 
   using LoadedScript = JS::loader::LoadedScript;
   using ScriptFetchOptions = JS::loader::ScriptFetchOptions;
@@ -143,6 +146,8 @@ class ModuleLoaderBase : public nsISupports {
  public:
   ScriptLoaderInterface* GetScriptLoaderInterface() const { return mLoader; }
 
+  nsIGlobalObject* GetGlobalObject() const { return mGlobalObject; }
+
   bool HasPendingDynamicImports() const;
   void CancelDynamicImport(ModuleLoadRequest* aRequest, nsresult aResult);
 #ifdef DEBUG