Introduce a Gin class instead of using global functions to control gin

gin/runner.cc

 // Copyright 2013 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 "gin/runner.h"
 
 #include "gin/converter.h"
 #include "gin/try_catch.h"
 
 using v8::Context;
@@ skipping 24 matching lines @@
 void RunnerDelegate::DidRunScript(Runner* runner, v8::Handle<Script> script) {
 }
 
 void RunnerDelegate::UnhandledException(Runner* runner, TryCatch& try_catch) {
 }
 
 Runner::Runner(RunnerDelegate* delegate, Isolate* isolate)
     : ContextHolder(isolate),
       delegate_(delegate),
       weak_factory_(this) {
+  v8::Isolate::Scope isolate_scope(isolate);
   HandleScope handle_scope(isolate);
   SetContext(Context::New(isolate, NULL, delegate_->GetGlobalTemplate(this)));
 
   v8::Context::Scope scope(context());
   delegate_->DidCreateContext(this);
 }
 
 Runner::~Runner() {
 }
 
 void Runner::Run(const std::string& script) {
   Run(Script::New(StringToV8(isolate(), script)));
 }
 
 void Runner::Run(v8::Handle<Script> script) {
   TryCatch try_catch;
   delegate_->WillRunScript(this, script);
   script->Run();
   delegate_->DidRunScript(this, script);
   if (try_catch.HasCaught())
     delegate_->UnhandledException(this, try_catch);
 }
 
 Runner::Scope::Scope(Runner* runner)
-    : handle_scope_(runner->isolate()),
+    : isolate_scope_(runner->isolate()),
+      handle_scope_(runner->isolate()),
       scope_(runner->context()) {
 }
 
 Runner::Scope::~Scope() {
 }
 
 }  // namespace gin