[ES6 modules] Fix context leak. ModuleScript should use TraceWrapperV8Reference to hold onto v8::Mo…

third_party/WebKit/Source/bindings/core/v8/ScriptModule.h

Index: third_party/WebKit/Source/bindings/core/v8/ScriptModule.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptModule.h b/third_party/WebKit/Source/bindings/core/v8/ScriptModule.h
index 05a79624a86083b4f98b9957d456c71515c3fc09..2dccaa579cff111bd2fba500e00b489e8e2f5999 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptModule.h
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptModule.h
@@ -77,8 +77,16 @@ class CORE_EXPORT ScriptModule final {
   bool IsNull() const { return !module_ || module_->IsEmpty(); }
 
  private:
+  // ModuleScript instances store their record as
+  // TraceWrapperV8Reference<v8::Module>, and reconstructs ScriptModule from it.
+  friend class ModuleScript;
+
   ScriptModule(v8::Isolate*, v8::Local<v8::Module>);
 
+  v8::Local<v8::Module> NewLocal(v8::Isolate* isolate) {
+    return module_->NewLocal(isolate);
+  }
+
   static v8::MaybeLocal<v8::Module> ResolveModuleCallback(
       v8::Local<v8::Context>,
       v8::Local<v8::String> specifier,