[ES6 modules] ModuleMap::GetFetchedModuleScript to return nullptr when entry not found / "fetching"

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

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef Modulator_h
 #define Modulator_h
 
 #include "core/CoreExport.h"
 #include "core/dom/AncestorList.h"
 #include "platform/bindings/ScriptWrappable.h"
@@ skipping 74 matching lines @@
   // https://html.spec.whatwg.org/#fetch-a-single-module-script
   virtual void FetchSingle(const ModuleScriptFetchRequest&,
                            ModuleGraphLevel,
                            SingleModuleClient*) = 0;
 
   virtual void FetchDescendantsForInlineScript(ModuleScript*,
                                                ModuleTreeClient*) = 0;
 
   // Synchronously retrieves a single module script from existing module map
   // entry.
-  // Note: returns nullptr if the module map entry is still "fetching".
+  // Note: returns nullptr if the module map entry doesn't exist, or
+  // is still "fetching".
   virtual ModuleScript* GetFetchedModuleScript(const KURL&) = 0;
 
   // https://html.spec.whatwg.org/#resolve-a-module-specifier
   static KURL ResolveModuleSpecifier(const String& module_request,
                                      const KURL& base_url);
 
   virtual ScriptModule CompileModule(const String& script,
                                      const String& url_str,
                                      AccessControlStatus) = 0;
 
@@ skipping 13 matching lines @@
   // if the cached entry doesn't exist.
   // The client can be notified either synchronously or asynchronously.
   virtual void FetchNewSingleModule(const ModuleScriptFetchRequest&,
                                     ModuleGraphLevel,
                                     ModuleScriptLoaderClient*) = 0;
 };
 
 }  // namespace blink
 
 #endif