Add chrome://popular-sites-internals/ to iOS.

components/ntp_tiles/webui/popular_sites_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_POPULAR_SITES_HANDLER_H_
+#define COMPONENTS_NTP_TILES_WEBUI_POPULAR_SITES_HANDLER_H_
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "base/callback.h"

[sdefresne, 2016/10/28 13:34:02]

#include "base/callback_forward.h" should be enough for the header (you'll need
to include "base/callback.h" in implementation).

[sfiera, 2016/10/28 14:12:43]

Done.

+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+
+class PrefService;
+
+namespace base {
+class Value;
+class ListValue;
+class SequencedWorkerPool;
+}  // namespace base
+
+namespace ntp_tiles {
+
+class PopularSites;
+
+class PopularSitesInternalsMessageHandlerInterface {

[Bernhard Bauer, 2016/10/28 13:23:07]

This is a bit weird:
1) Two classes defined in the same file, none of which match the filename
2) The ...Impl class does not actually implement the ...Interface class (and
...Interface is neither required in Chrome, nor common, but maybe I'm just
misunderstanding how this is supposed to work). Can you shed some light onto
that?

[sdefresne, 2016/10/28 13:34:02]

Is this an interface implemented by embedder (desktop, ios, ...) and injected in
the component? If so, the convention for other components  is to call them
FooClient.

[sfiera, 2016/10/28 13:38:14]

Basically, the problem is that the WebUI handlers for content and for ios have
the same methods (or almost the same), but don't share an interface.

So there are two "PopularSitesInternalsMessageHandler" classes, one for content
(under //chrome), and one for ios (under //ios/chrome). They both implement
…Interface, which is the message handler methods, plus a bit more factory stuff
for popular sites specifically. Then they both use …Impl for their
implementation, except for the stuff that's actually different on the platforms.

This file could be popular_sites_internals_message_handler_impl.h.

[sfiera, 2016/10/28 14:12:43]

Renamed to Client.

+ public:

[sdefresne, 2016/10/28 13:34:02]

The class needs a virtual destructor.

[sfiera, 2016/10/28 14:12:43]

Done.

+  virtual base::SequencedWorkerPool* GetBlockingPool() = 0;

[sdefresne, 2016/10/28 13:34:02]

Can you document this class and its methods?

[sfiera, 2016/10/28 14:12:42]

Done.

+  virtual std::unique_ptr<ntp_tiles::PopularSites> MakePopularSites() = 0;
+  virtual PrefService* GetPrefs() = 0;
+  virtual void RegisterMessageCallback(
+      const std::string& message,
+      const base::Callback<void(const base::ListValue*)>& callback) = 0;
+  virtual void CallJavascriptFunctionVector(
+      const std::string& name,
+      const std::vector<const base::Value*>& values) = 0;
+
+  template <typename... Arg>
+  void CallJavascriptFunction(const std::string& name, const Arg&... arg) {
+    CallJavascriptFunctionVector(name, {&arg...});
+  }

[sdefresne, 2016/10/28 13:34:03]

I would recommend making the class non-copyable since it has virtual methods.

[sfiera, 2016/10/28 14:12:42]

Done.

[Bernhard Bauer, 2016/10/28 16:56:38]

OOC, why are virtual methods the criterium here? What I've always heard was that
a non-trivial destructor means that copy and assignment constructors should
either be explicitly written, or explicitly disallowed
(https://en.wikipedia.org/wiki/Rule_of_three_(C%2B%2B_programming) ).

+};
+
+class PopularSitesInternalsMessageHandlerImpl {

[sdefresne, 2016/10/28 13:34:02]

Can you document this class and its methods?

[sfiera, 2016/10/28 14:12:42]

Done. (the public ones—most of them actually no longer needed to be public)

+ public:
+  PopularSitesInternalsMessageHandlerImpl(
+      PopularSitesInternalsMessageHandlerInterface* web_ui);
+  ~PopularSitesInternalsMessageHandlerImpl();
+
+  void RegisterMessages();
+
+  void HandleRegisterForEvents(const base::ListValue* args);
+  void HandleUpdate(const base::ListValue* args);
+  void HandleViewJson(const base::ListValue* args);
+
+  void SendOverrides();
+  void SendDownloadResult(bool success);
+  void SendSites();
+  void SendJson(const std::string& json);
+
+  void OnPopularSitesAvailable(bool explicit_request, bool success);
+
+ private:
+  std::unique_ptr<PopularSites> popular_sites_;
+  PopularSitesInternalsMessageHandlerInterface* web_ui_;
+  base::WeakPtrFactory<PopularSitesInternalsMessageHandlerImpl>
+      weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(PopularSitesInternalsMessageHandlerImpl);
+};
+
+}  // namespace ntp_tiles
+
+#endif  // COMPONENTS_NTP_TILES_WEBUI_POPULAR_SITES_HANDLER_H_