Clean up plug-in placeholders:

chrome/renderer/plugins/missing_plugin.h

+// Copyright (c) 2011 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_RENDERER_PLUGINS_MISSING_PLUGIN_H_
+#define CHROME_RENDERER_PLUGINS_MISSING_PLUGIN_H_
+#pragma once
+
+#include "chrome/renderer/plugins/plugin_placeholder.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebString.h"
+
+class MissingPlugin : public PluginPlaceholder {
+ public:
+  // Creates a new WebViewPlugin with a MissingPlugin as a delegate.
+  static webkit::WebViewPlugin* Create(
+      content::RenderView* render_view,
+      WebKit::WebFrame* frame,
+      const WebKit::WebPluginParams& params);
+
+ private:
+  MissingPlugin(content::RenderView* render_view,
+                WebKit::WebFrame* frame,
+                const WebKit::WebPluginParams& params,
+                const std::string& html_data);
+  virtual ~MissingPlugin();
+
+  // WebViewPlugin::Delegate methods:
+  virtual void BindWebFrame(WebKit::WebFrame* frame) OVERRIDE;
+  virtual void ShowContextMenu(const WebKit::WebMouseEvent&) OVERRIDE;
+
+  // content::RenderViewObserver methods:
+  virtual void ContextMenuAction(unsigned id) OVERRIDE;
+
+  void HideCallback(const CppArgumentList& args, CppVariant* result);
+
+  WebKit::WebString mime_type_;
+
+  DISALLOW_COPY_AND_ASSIGN(MissingPlugin);
+};
+
+#endif  // CHROME_RENDERER_PLUGINS_MISSING_PLUGIN_H_