Split out the extensions gin::Runner implementation into a separate class.

extensions/renderer/module_system_test.cc

 // Copyright 2014 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 "extensions/renderer/module_system_test.h"
 
 #include <map>
 #include <string>
 
 #include "base/callback.h"
@@ skipping 138 matching lines @@
       "logging",
       scoped_ptr<NativeHandler>(new LoggingNativeHandler(context_.get())));
   module_system->RegisterNativeHandler(
       "utils",
       scoped_ptr<NativeHandler>(new UtilsNativeHandler(context_.get())));
   module_system->SetExceptionHandlerForTest(
       scoped_ptr<ModuleSystem::ExceptionHandler>(new FailsOnException));
 }
 
 ModuleSystemTestEnvironment::~ModuleSystemTestEnvironment() {
-  if (context_)
+  if (context_->is_valid())
     context_->v8_context()->Exit();
 }
 
 void ModuleSystemTestEnvironment::RegisterModule(const std::string& name,
                                                  const std::string& code) {
   source_map_->RegisterModule(name, code);
 }
 
 void ModuleSystemTestEnvironment::RegisterModule(const std::string& name,
                                                  int resource_id) {
@@ skipping 20 matching lines @@
   ASSERT_TRUE(base::ReadFileToString(test_js_file_path, &test_js));
   source_map_->RegisterModule(module_name, test_js);
 }
 
 void ModuleSystemTestEnvironment::ShutdownGin() {
   context_holder_.reset();
 }
 
 void ModuleSystemTestEnvironment::ShutdownModuleSystem() {
   context_->v8_context()->Exit();
-  context_.reset();
+  context_->Invalidate();
 }
 
 v8::Handle<v8::Object> ModuleSystemTestEnvironment::CreateGlobal(
     const std::string& name) {
   v8::EscapableHandleScope handle_scope(isolate_);
   v8::Local<v8::Object> object = v8::Object::New(isolate_);
   isolate_->GetCurrentContext()->Global()->Set(
       v8::String::NewFromUtf8(isolate_, name.c_str()), object);
   return handle_scope.Escape(object);
 }
@@ skipping 35 matching lines @@
 
 void ModuleSystemTest::ExpectNoAssertionsMade() {
   should_assertions_be_made_ = false;
 }
 
 void ModuleSystemTest::RunResolvedPromises() {
   isolate_->RunMicrotasks();
 }
 
 }  // namespace extensions