Add migration code for the EnabledPlugins and DisabledPlugins policies.

chrome/browser/plugins/plugin_policy_handler.h

+// Copyright (c) 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 CHROME_BROWSER_PLUGINS_PLUGIN_POLICY_HANDLER_H_
+#define CHROME_BROWSER_PLUGINS_PLUGIN_POLICY_HANDLER_H_
+
+#include <map>
+#include <set>
+#include <vector>
+
+#include "base/macros.h"
+#include "chrome/browser/plugins/plugin_prefs.h"
+#include "components/content_settings/core/common/content_settings.h"
+#include "components/policy/core/browser/configuration_policy_handler.h"
+#include "components/policy/policy_constants.h"
+#include "components/prefs/pref_value_map.h"
+
+// Migrates values of deprecated plugin policies into their new counterpars.
+// It reads the set of EnabledPlugins and DisabledPlugins and updates the Flash
+// default behavior and PDF plugin behavior. All other values in the list are
+// ignored.
+class PluginPolicyHandler : public policy::ConfigurationPolicyHandler {
+ public:
+  PluginPolicyHandler();
+  ~PluginPolicyHandler() override;
+
+ protected:
+  bool CheckPolicySettings(const policy::PolicyMap& policies,
+                           policy::PolicyErrorMap* errors) override;
+  void ApplyPolicySettings(const policy::PolicyMap& policies,
+                           PrefValueMap* prefs) override;
+
+ private:
+  void ProcessPolicy(const policy::PolicyMap& policies,
+                     PrefValueMap* prefs,
+                     const std::string& policy,
+                     bool disable_pdf_plugin,
+                     ContentSetting flash_content_setting);
+
+  DISALLOW_COPY_AND_ASSIGN(PluginPolicyHandler);
+};
+
+#endif  // CHROME_BROWSER_PLUGINS_PLUGIN_POLICY_HANDLER_H_