Introduce ModulePendingScript

third_party/WebKit/Source/core/dom/Modulator.h

Index: third_party/WebKit/Source/core/dom/Modulator.h
diff --git a/third_party/WebKit/Source/core/dom/Modulator.h b/third_party/WebKit/Source/core/dom/Modulator.h
index ef95e0b48bf21f23ff408d924aa9dd71da8f2474..ad1d58268c8499f258563614d9c20449aefc4e11 100644
--- a/third_party/WebKit/Source/core/dom/Modulator.h
+++ b/third_party/WebKit/Source/core/dom/Modulator.h
@@ -34,6 +34,13 @@ class SingleModuleClient : public GarbageCollectedMixin {
   virtual void NotifyModuleLoadFinished(ModuleScript*) = 0;
 };
 
+// A ModuleTreeClient is notified when a module script and its whole descendent
+// tree load is complete.
+class ModuleTreeClient : public GarbageCollectedMixin {
+ public:
+  virtual void NotifyModuleTreeLoadFinished(ModuleScript*) = 0;
+};
+
 // spec: "top-level module fetch flag"
 // https://html.spec.whatwg.org/multipage/webappapis.html#fetching-scripts-is-top-level
 enum class ModuleGraphLevel { kTopLevelModuleFetch, kDependentModuleFetch };