Upstream the iOS web_shell and supporting code

ios/web/shell/shell_main_delegate.h

+// 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.
+
+#ifndef IOS_WEB_SHELL_SHELL_MAIN_DELEGATE_H_
+#define IOS_WEB_SHELL_SHELL_MAIN_DELEGATE_H_
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "ios/web/public/app/web_main_delegate.h"
+
+namespace web {
+class ShellWebClient;
+
+class ShellMainDelegate : public WebMainDelegate {
+ public:
+  ShellMainDelegate();
+  ~ShellMainDelegate() override;
+
+  void BasicStartupComplete() override;
+
+ private:
+  scoped_ptr<ShellWebClient> web_client_;
+};
+
+}  // namespace web
+
+#endif  // IOS_WEB_SHELL_SHELL_MAIN_DELEGATE_H_