Add Application version and OS info in android about version page.

chrome/browser/ui/android/android_about_app_info.h

+// Copyright (c) 2012 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 CHROME_BROWSER_UI_ANDROID_ANDROID_ABOUT_APP_INFO_H_
+#define CHROME_BROWSER_UI_ANDROID_ANDROID_ABOUT_APP_INFO_H_
+
+#include <string>
+
+class AndroidAboutAppInfo {
+ public:
+  // Returns a string containing detailed info about the os environment.
+  static std::string GetOsInfo();
+};
+
+#endif  // CHROME_BROWSER_UI_ANDROID_ANDROID_ABOUT_APP_INFO_H_