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

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

 // 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.
 
 #include "core/dom/ModuleScript.h"
 
 #include "bindings/core/v8/ScriptValue.h"
 #include "core/dom/ScriptModuleResolver.h"
 #include "platform/bindings/ScriptState.h"
 #include "v8/include/v8.h"
@@ skipping 60 matching lines @@
     ScriptModule record,
     const KURL& base_url,
     const String& nonce,
     ParserDisposition parser_state,
     WebURLRequest::FetchCredentialsMode credentials_mode) {
   String dummy_source_text = "";
   return CreateInternal(dummy_source_text, modulator, record, base_url, nonce,
                         parser_state, credentials_mode);
 }
 
+ModuleScript::ModuleScript(Modulator* settings_object,
+                           ScriptModule record,
+                           const KURL& base_url,
+                           const String& nonce,
+                           ParserDisposition parser_state,
+                           WebURLRequest::FetchCredentialsMode credentials_mode,
+                           const String& source_text)
+    : settings_object_(settings_object),
+      record_(this),
+      base_url_(base_url),
+      instantiation_error_(this),
+      nonce_(nonce),
+      parser_state_(parser_state),
+      credentials_mode_(credentials_mode),
+      source_text_(source_text) {
+  if (record.IsNull()) {
+    // We allow empty records for module infra tests which never touch records.
+    // This should never happen outside unit tests.
+    return;
+  }
+
+  DCHECK(settings_object);
+  v8::Isolate* isolate = settings_object_->GetScriptState()->GetIsolate();
+  v8::HandleScope scope(isolate);
+  record_.Set(isolate, record.NewLocal(isolate));
+}
+
+ScriptModule ModuleScript::Record() const {
+  if (record_.IsEmpty())
+    return ScriptModule();
+
+  v8::Isolate* isolate = settings_object_->GetScriptState()->GetIsolate();
+  v8::HandleScope scope(isolate);
+  return ScriptModule(isolate, record_.NewLocal(isolate));
+}
+
 void ModuleScript::SetInstantiationErrorAndClearRecord(ScriptValue error) {
   // Implements Step 7.1 of:
   // https://html.spec.whatwg.org/multipage/webappapis.html#internal-module-script-graph-fetching-procedure
 
   // "set script's instantiation state to "errored", ..."
   DCHECK_EQ(instantiation_state_, ModuleInstantiationState::kUninstantiated);
   instantiation_state_ = ModuleInstantiationState::kErrored;
 
   // "its instantiation error to instantiationStatus.[[Value]], and ..."
   DCHECK(!error.IsEmpty());
   {
     ScriptState::Scope scope(error.GetScriptState());
     instantiation_error_.Set(error.GetIsolate(), error.V8Value());
   }
 
   // "its module record to null."
-  record_ = ScriptModule();
+  record_.Clear();
 }
 
 void ModuleScript::SetInstantiationSuccess() {
   // Implements Step 7.2 of:
   // https://html.spec.whatwg.org/multipage/webappapis.html#internal-module-script-graph-fetching-procedure
 
   // "set script's instantiation state to "instantiated"."
   DCHECK_EQ(instantiation_state_, ModuleInstantiationState::kUninstantiated);
   instantiation_state_ = ModuleInstantiationState::kInstantiated;
 }
 
 DEFINE_TRACE(ModuleScript) {
   visitor->Trace(settings_object_);
   Script::Trace(visitor);
 }
 DEFINE_TRACE_WRAPPERS(ModuleScript) {
+  // TODO(mlippautz): Support TraceWrappers(const
+  // TraceWrapperV8Reference<v8::Module>&) to remove the cast.
+  visitor->TraceWrappers(record_.Cast<v8::Value>());
   visitor->TraceWrappers(instantiation_error_);
 }
 
 bool ModuleScript::IsEmpty() const {
   return false;
 }
 
 bool ModuleScript::CheckMIMETypeBeforeRunScript(Document* context_document,
                                                 const SecurityOrigin*) const {
   // We don't check MIME type here because we check the MIME type in
   // ModuleScriptLoader::WasModuleLoadSuccessful().
   return true;
 }
 
 void ModuleScript::RunScript(LocalFrame* frame, const SecurityOrigin*) const {
   settings_object_->ExecuteModule(this);
 }
 
 String ModuleScript::InlineSourceTextForCSP() const {
   return source_text_;
 }
 
 }  // namespace blink