Refactor the about:version code out of about_ui.

chrome/browser/ui/webui/version_handler_chromeos.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_WEBUI_VERSION_HANDLER_CHROMEOS_H_
+#define CHROME_BROWSER_UI_WEBUI_VERSION_HANDLER_CHROMEOS_H_
+
+#include <string>
+
+#include "chrome/browser/chromeos/version_loader.h"
+#include "chrome/browser/ui/webui/version_handler.h"
+
+// VersionHandlerChromeOS is responsible for loading the Chrome OS
+// version.
+class VersionHandlerChromeOS : public VersionHandler {
+ public:
+  VersionHandlerChromeOS();
+  virtual ~VersionHandlerChromeOS();
+
+  // VersionHandler overrides:
+  virtual void HandleRequestVersionInfo(const ListValue* args) OVERRIDE;
+
+  // Callback from chromeos::VersionLoader giving the version.
+  void OnVersion(chromeos::VersionLoader::Handle handle,
+                 const std::string& version);
+
+ private:
+  // Handles asynchronously loading the version.
+  chromeos::VersionLoader loader_;
+
+  // Used to request the version.
+  CancelableRequestConsumer consumer_;
+
+  DISALLOW_COPY_AND_ASSIGN(VersionHandlerChromeOS);
+};
+
+#endif  // CHROME_BROWSER_UI_WEBUI_VERSION_HANDLER_CHROMEOS_H_