[ES6 modules] Introduce ScriptModuleHash

third_party/WebKit/Source/bindings/core/v8/ScriptModule.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 "bindings/core/v8/ScriptModule.h"
 
 #include "bindings/core/v8/V8Binding.h"
 
 namespace blink {
 
 ScriptModule::ScriptModule(v8::Isolate* isolate, v8::Local<v8::Module> module)
-    : m_module(SharedPersistent<v8::Module>::create(module, isolate)) {}
+    : m_module(SharedPersistent<v8::Module>::create(module, isolate)),
+      m_identityHash(static_cast<unsigned>(module->GetIdentityHash())) {
+  DCHECK(!m_module.isEmpty());
+}
 
 ScriptModule::~ScriptModule() {}
 
 ScriptModule ScriptModule::compile(v8::Isolate* isolate,
                                    const String& source,
                                    const String& fileName) {
   v8::TryCatch tryCatch(isolate);
   tryCatch.SetVerbose(true);
   v8::Local<v8::Module> module;
   if (!v8Call(V8ScriptRunner::compileModule(isolate, source, fileName), module,
@@ skipping 24 matching lines @@
   tryCatch.SetVerbose(true);
   v8::Local<v8::Value> result;
   if (!v8Call(V8ScriptRunner::evaluateModule(m_module->newLocal(isolate),
                                              scriptState->context(), isolate),
               result, tryCatch)) {
     // TODO(adamk): report error
   }
 }
 
 }  // namespace blink