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

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

Index: third_party/WebKit/Source/core/dom/ModuleScript.h
diff --git a/third_party/WebKit/Source/core/dom/ModuleScript.h b/third_party/WebKit/Source/core/dom/ModuleScript.h
index 76e42e8c1b7ac184eef3e0777b1db62752499abc..2f4bbbcd7fa79a9e93253d48153140d80dc17893 100644
--- a/third_party/WebKit/Source/core/dom/ModuleScript.h
+++ b/third_party/WebKit/Source/core/dom/ModuleScript.h
@@ -53,7 +53,7 @@ class CORE_EXPORT ModuleScript final : public Script, public TraceWrapperBase {
 
   ~ModuleScript() override = default;
 
-  const ScriptModule& Record() const { return record_; }
+  ScriptModule Record() const;
   const KURL& BaseURL() const { return base_url_; }
 
   ModuleInstantiationState InstantiationState() const {
@@ -87,15 +87,7 @@ class CORE_EXPORT ModuleScript final : public Script, public TraceWrapperBase {
                const String& nonce,
                ParserDisposition parser_state,
                WebURLRequest::FetchCredentialsMode credentials_mode,
-               const String& source_text)
-      : settings_object_(settings_object),
-        record_(record),
-        base_url_(base_url),
-        instantiation_error_(this),
-        nonce_(nonce),
-        parser_state_(parser_state),
-        credentials_mode_(credentials_mode),
-        source_text_(source_text) {}
+               const String& source_text);
 
   static ModuleScript* CreateInternal(const String& source_text,
                                       Modulator*,
@@ -125,7 +117,7 @@ class CORE_EXPORT ModuleScript final : public Script, public TraceWrapperBase {
   Member<Modulator> settings_object_;
 
   // https://html.spec.whatwg.org/multipage/webappapis.html#concept-module-script-module-record
-  ScriptModule record_;
+  TraceWrapperV8Reference<v8::Module> record_;
 
   // https://html.spec.whatwg.org/multipage/webappapis.html#concept-module-script-base-url
   const KURL base_url_;