media: Enable ProtectedMediaIdentifierPermissionContext on ChromeOS.

chrome/browser/media/protected_media_identifier_permission_context_factory.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/media/protected_media_identifier_permission_context_factory.h"
 
 #include "chrome/browser/media/protected_media_identifier_permission_context.h"
 #include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/pref_names.h"
@@ skipping 29 matching lines @@
 KeyedService*
 ProtectedMediaIdentifierPermissionContextFactory::BuildServiceInstanceFor(
     content::BrowserContext* profile) const {
   return new ProtectedMediaIdentifierPermissionContext(
       static_cast<Profile*>(profile));
 }
 
 void
 ProtectedMediaIdentifierPermissionContextFactory::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
+#if defined(OS_ANDROID)
   registry->RegisterBooleanPref(
       prefs::kProtectedMediaIdentifierEnabled,
       true,
       user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+#endif
 }
 
 content::BrowserContext*
 ProtectedMediaIdentifierPermissionContextFactory::GetBrowserContextToUse(
     content::BrowserContext* context) const {
   return chrome::GetBrowserContextOwnInstanceInIncognito(context);
 }