Add chrome://site-tiles-internals/

components/ntp_tiles/webui/ntp_tiles_internals_message_handler.h

+// Copyright 2016 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 COMPONENTS_NTP_TILES_WEBUI_NTP_TILES_INTERNALS_MESSAGE_HANDLER_H_
+#define COMPONENTS_NTP_TILES_WEBUI_NTP_TILES_INTERNALS_MESSAGE_HANDLER_H_
+
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "components/ntp_tiles/most_visited_sites.h"
+
+namespace base {
+class ListValue;
+}  // namespace base
+
+namespace ntp_tiles {
+
+class MostVisitedSites;
+class NTPTilesInternalsMessageHandlerClient;
+
+// Implements the WebUI message handler for chrome://ntp-tiles-internals/
+//
+// Because content and iOS use different implementations of WebUI, this class
+// implements the generic portion and depends on the embedder to inject a bridge
+// to the embedder's API. It cannot itself implement either API directly.
+class NTPTilesInternalsMessageHandler : public MostVisitedSites::Observer {
+ public:
+  NTPTilesInternalsMessageHandler();
+  ~NTPTilesInternalsMessageHandler() override;
+
+  // Called when the WebUI page's JavaScript has loaded and it is ready to
+  // receive RegisterMessageCallback() calls. |client| must outlive this object.
+  void RegisterMessages(NTPTilesInternalsMessageHandlerClient* client);
+
+ private:
+  // Callbacks registered in RegisterMessages().
+  void HandleRegisterForEvents(const base::ListValue* args);
+  void HandleUpdate(const base::ListValue* args);
+
+  void SendSourceInfo();
+  void SendTiles(const NTPTilesVector& tiles);
+
+  // MostVisitedSites::Observer.
+  void OnMostVisitedURLsAvailable(const NTPTilesVector& tiles) override;
+  void OnIconMadeAvailable(const GURL& site_url) override;
+
+  // Bridge to embedder's API.
+  NTPTilesInternalsMessageHandlerClient* client_;
+
+  int site_count_;
+  std::unique_ptr<MostVisitedSites> most_visited_sites_;
+
+  DISALLOW_COPY_AND_ASSIGN(NTPTilesInternalsMessageHandler);
+};
+
+}  // namespace ntp_tiles
+
+#endif  // COMPONENTS_NTP_TILES_WEBUI_NTP_TILES_INTERNALS_MESSAGE_HANDLER_H_