Add chrome://site-tiles-internals/

components/ntp_tiles/webui/site_tiles_internals_message_handler_client.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_SITE_TILES_HANDLER_CLIENT_H_
+#define COMPONENTS_NTP_TILES_WEBUI_SITE_TILES_HANDLER_CLIENT_H_

[Marc Treib, 2016/12/08 15:41:50]

Doesn't match the file name

[sfiera, 2016/12/08 16:44:35]

Done.

+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "base/callback_forward.h"
+#include "base/macros.h"
+#include "components/ntp_tiles/ntp_tile_source.h"
+
+class PrefService;
+
+namespace base {
+class Value;
+class ListValue;
+class SequencedWorkerPool;
+}  // namespace base
+
+namespace ntp_tiles {
+
+class MostVisitedSites;
+class PopularSites;
+
+// Implemented by embedders to hook up SiteTilesInternalsMessageHandler.
+class SiteTilesInternalsMessageHandlerClient {
+ public:
+  // Returns the blocking pool for hte embedder.

[Marc Treib, 2016/12/08 15:41:50]

s/hte/the/

[sfiera, 2016/12/08 16:44:35]

Done.

+  virtual base::SequencedWorkerPool* GetBlockingPool() = 0;
+
+  // Returns the PrefService for the embedder and containing WebUI page.
+  virtual PrefService* GetPrefs() = 0;
+
+  // Returns true if the given source is enabled (even if, in practice, none of
+  // the tiles would come from it).
+  virtual bool IsSourceEnabled(NTPTileSource source) = 0;
+
+  // Creates a new MostVisited based on the context pf the WebUI page.

[Marc Treib, 2016/12/08 15:41:50]

s/pf/of/, also below

+  virtual std::unique_ptr<ntp_tiles::MostVisitedSites>
+  MakeMostVisitedSites() = 0;
+
+  // Creates a new PopularSites based on the context pf the WebUI page.
+  virtual std::unique_ptr<ntp_tiles::PopularSites> MakePopularSites() = 0;
+
+  // Registers a callback in Javascript. See content::WebUI and web::WebUIIOS.
+  virtual void RegisterMessageCallback(
+      const std::string& message,
+      const base::Callback<void(const base::ListValue*)>& callback) = 0;
+
+  // Invokes a function in Javascript. See content::WebUI and web::WebUIIOS.
+  virtual void CallJavascriptFunctionVector(
+      const std::string& name,
+      const std::vector<const base::Value*>& values) = 0;
+
+  // Helper function for CallJavascriptFunctionVector().
+  template <typename... Arg>
+  void CallJavascriptFunction(const std::string& name, const Arg&... arg) {
+    CallJavascriptFunctionVector(name, {&arg...});

[Marc Treib, 2016/12/08 15:41:50]

This is a bit yucky... since we only seem to have single-argument
CallJavascriptFunction invocations anyway, maybe get rid of this?

[sfiera, 2016/12/08 16:44:35]

(discussed elsewhere)

+  }
+
+ protected:
+  SiteTilesInternalsMessageHandlerClient();
+  virtual ~SiteTilesInternalsMessageHandlerClient();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SiteTilesInternalsMessageHandlerClient);
+};
+
+}  // namespace ntp_tiles
+
+#endif  // COMPONENTS_NTP_TILES_WEBUI_SITE_TILES_HANDLER_CLIENT_H_