Add a SigninAllowed policy.

chrome/browser/profiles/profile_impl.cc

 // Copyright (c) 2012 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/profiles/profile_impl.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
@@ skipping 254 matching lines @@
 int ProfileImpl::create_readme_delay_ms = 60000;
 
 // static
 const char* const ProfileImpl::kPrefExitTypeNormal = "Normal";
 
 // static
 void ProfileImpl::RegisterUserPrefs(PrefServiceSyncable* prefs) {
   prefs->RegisterBooleanPref(prefs::kSavingBrowserHistoryDisabled,
                              false,
                              PrefServiceSyncable::UNSYNCABLE_PREF);
+  prefs->RegisterBooleanPref(prefs::kSigninAllowed,
+                             true,
+                             PrefServiceSyncable::UNSYNCABLE_PREF);
   prefs->RegisterBooleanPref(prefs::kForceSafeSearch,
                              false,
                              PrefServiceSyncable::UNSYNCABLE_PREF);
   prefs->RegisterIntegerPref(prefs::kProfileAvatarIndex,
                              -1,
                              PrefServiceSyncable::SYNCABLE_PREF);
   prefs->RegisterStringPref(prefs::kProfileName,
                             "",
                             PrefServiceSyncable::SYNCABLE_PREF);
   prefs->RegisterBooleanPref(prefs::kProfileIsManaged,
@@ skipping 864 matching lines @@
                                      FilePath* cache_path,
                                      int* max_size) {
   DCHECK(cache_path);
   DCHECK(max_size);
   FilePath path(prefs_->GetFilePath(prefs::kDiskCacheDir));
   if (!path.empty())
     *cache_path = path;
   *max_size = is_media_context ? prefs_->GetInteger(prefs::kMediaCacheSize) :
                                  prefs_->GetInteger(prefs::kDiskCacheSize);
 }