Enable NPAPI if policy has plugin policies.

chrome/browser/plugins/plugin_policy_handler.cc

+// 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.
+
+#include "chrome/browser/plugins/plugin_policy_handler.h"
+
+#include "base/logging.h"
+#include "base/prefs/pref_value_map.h"
+#include "base/values.h"
+#include "chrome/common/pref_names.h"
+#include "components/policy/core/browser/policy_error_map.h"
+#include "components/policy/core/common/policy_map.h"
+#include "policy/policy_constants.h"
+
+namespace policy {
+
+PluginPolicyHandler::PluginPolicyHandler(
+    const char* policy_name,
+    const char* pref_path,
+    base::Value::Type value_type)
+    : TypeCheckingPolicyHandler(policy_name, value_type),
+      pref_path_(pref_path) {
+}
+
+PluginPolicyHandler::~PluginPolicyHandler() {}
+
+void PluginPolicyHandler::ApplyPolicySettings(const PolicyMap& policies,
+                                              PrefValueMap* prefs) {
+  if (!pref_path_)
+    return;
+  const base::Value* value = policies.GetValue(policy_name());
+  if (value) {
+    prefs->SetBoolean(prefs::kEnableNpapi, true);

[Mattias Nissler (ping if slow), 2015/04/10 08:47:15]

You have multiple instances of this policy handler, and they all write to the
same pref key. This is  frowned upon, as the result will generally depend on the
order in which the handlers run. Admittedly, that's not the case here as setting
the pref to true multiple times will give the same result regardless of order.

For consistency, I'd still prefer a solution that just keeps the
SimplePolicyHandlers for mapping the existing plugin policy settings to prefs,
and then an additional handler that is solely responsible for mapping policy to
prefs::kEnableNpapi.

[Will Harris, 2015/04/10 18:51:23]

Done.

+    prefs->SetValue(pref_path_, value->DeepCopy());
+  }
+}
+
+}  // namespace policy