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

gin/shell/gin_main.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 "base/at_exit.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
+#include "base/i18n/icu_util.h"
 #include "base/message_loop/message_loop.h"
-#include "gin/initialize.h"
+#include "gin/gin.h"
 #include "gin/modules/console.h"
 #include "gin/modules/module_runner_delegate.h"
 #include "gin/test/file_runner.h"
 #include "gin/try_catch.h"
 
 namespace gin {
 namespace {
 
 std::string Load(const base::FilePath& path) {
   std::string source;
@@ skipping 30 matching lines @@
  private:
   DISALLOW_COPY_AND_ASSIGN(ShellRunnerDelegate);
 };
 
 }  // namespace
 }  // namespace gin
 
 int main(int argc, char** argv) {
   base::AtExitManager at_exit;
   CommandLine::Init(argc, argv);
-  gin::Initialize();
+  base::i18n::InitializeICU();
+
+  gin::Gin instance;
 
   base::MessageLoop message_loop;
 
   gin::ShellRunnerDelegate delegate;
-  gin::Runner runner(&delegate, v8::Isolate::GetCurrent());
+  gin::Runner runner(&delegate, instance.isolate());
 
   CommandLine::StringVector args = CommandLine::ForCurrentProcess()->GetArgs();
   for (CommandLine::StringVector::const_iterator it = args.begin();
        it != args.end(); ++it) {
     base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
         gin::Run, runner.GetWeakPtr(), gin::Load(base::FilePath(*it))));
   }
 
   message_loop.RunUntilIdle();
   return 0;
 }