Add initial version of chrome://popular-sites-internals page

chrome/browser/ui/webui/popular_sites_internals_message_handler.h

+// Copyright 2015 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_POPULAR_SITES_INTERNALS_MESSAGE_HANDLER_H_
+#define CHROME_BROWSER_UI_WEBUI_POPULAR_SITES_INTERNALS_MESSAGE_HANDLER_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "content/public/browser/web_ui_message_handler.h"
+
+namespace base {
+class ListValue;
+}  // namespace base
+
+class PopularSites;
+
+// The implementation for the chrome://popular-sites-internals page.
+class PopularSitesInternalsMessageHandler
+    : public content::WebUIMessageHandler {
+ public:
+  PopularSitesInternalsMessageHandler();
+  ~PopularSitesInternalsMessageHandler() override;
+
+ private:
+  // content::WebUIMessageHandler:
+  void RegisterMessages() override;
+
+  void HandleRegisterForEvents(const base::ListValue* args);
+  void HandleDownload(const base::ListValue* args);
+
+  void SendDownloadResult(bool success);
+  void SendSites();
+
+  void OnPopularSitesAvailable(bool explicit_request, bool success);
+
+  scoped_ptr<PopularSites> popular_sites_;
+
+  DISALLOW_COPY_AND_ASSIGN(PopularSitesInternalsMessageHandler);
+};
+
+#endif  // CHROME_BROWSER_UI_WEBUI_POPULAR_SITES_INTERNALS_MESSAGE_HANDLER_H_