Remove plugins::MobileYouTubePlugin, deprecated by Flash embed override.

components/plugins/renderer/mobile_youtube_plugin.h

-// Copyright 2013 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_PLUGINS_RENDERER_MOBILE_YOUTUBE_PLUGIN_H_
-#define COMPONENTS_PLUGINS_RENDERER_MOBILE_YOUTUBE_PLUGIN_H_
-
-#include "base/macros.h"
-#include "components/plugins/renderer/plugin_placeholder.h"
-
-namespace plugins {
-
-// Class representing placeholders for old style embedded youtube video on
-// mobile device. For old style embedded youtube video, it has a url in the form
-// of http://www.youtube.com/v/VIDEO_ID. This placeholder replaces the url with
-// a simple html page and clicking the play image redirects the user to the
-// mobile youtube app.
-class MobileYouTubePlugin final : public PluginPlaceholderBase,
-                                  public gin::Wrappable<MobileYouTubePlugin> {
- public:
-  static gin::WrapperInfo kWrapperInfo;
-
-  MobileYouTubePlugin(content::RenderFrame* render_frame,
-                      blink::WebLocalFrame* frame,
-                      const blink::WebPluginParams& params,
-                      base::StringPiece& template_html);
-
-  // Whether this is a youtube url.
-  static bool IsYouTubeURL(const GURL& url, const std::string& mime_type);
-
- private:
-  ~MobileYouTubePlugin() override;
-
-  // Opens a youtube app in the current tab.
-  void OpenYoutubeUrlCallback();
-
-  // WebViewPlugin::Delegate methods:
-  v8::Local<v8::Value> GetV8Handle(v8::Isolate* isolate) override;
-
-  // gin::Wrappable (via PluginPlaceholder) method
-  gin::ObjectTemplateBuilder GetObjectTemplateBuilder(
-      v8::Isolate* isolate) final;
-
-  DISALLOW_COPY_AND_ASSIGN(MobileYouTubePlugin);
-};
-
-}  // namespace plugins
-
-#endif  // COMPONENTS_PLUGINS_RENDERER_MOBILE_YOUTUBE_PLUGIN_H_