Add PluginServiceFilter interface.

content/browser/plugin_filter.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 CONTENT_BROWSER_PLUGIN_FILTER_H_
+#define CONTENT_BROWSER_PLUGIN_FILTER_H_
+#pragma once
+
+// Callback class to let the client filter the list of all installed plug-ins.
+// This class is called on the FILE thread.
+class PluginFilter {
+ public:
+  virtual ~PluginFilter() {}
+  // Whether to use |plugin|. The client can return false to disallow the
+  // plugin, or return true and optionally change the passed in plugin.
+  virtual bool ShouldUsePlugin(webkit::npapi::WebPluginInfo* plugin) = 0;
+};
+
+#endif  // CONTENT_BROWSER_PLUGIN_FILTER_H_