Add a device policy for specifying the release channel.

chrome/browser/chromeos/login/signed_settings.cc

 // 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.
 
 #include "chrome/browser/chromeos/login/signed_settings.h"
 
 #include <string>
 #include <vector>
 
 #include "base/memory/ref_counted.h"
@@ skipping 734 matching lines @@
     return kVeritas[pol.data_roaming_enabled().data_roaming_enabled()];
 
   } else if (prop == kSettingProxyEverywhere) {
     // TODO(cmasone): NOTIMPLEMENTED() once http://crosbug.com/13052 is fixed.
     std::string serialized;
     if (!pol.has_device_proxy_settings() ||
         !pol.device_proxy_settings().SerializeToString(&serialized))
       return "";           // Default to invalid proxy config (will be ignored).
     return serialized;
 
+  } else if (prop == kReleaseChannel) {
+    if (!pol.has_release_channel() ||
+        !pol.release_channel().has_release_channel())
+      return "";           // Default: don't change the release channel
+    return pol.release_channel().release_channel();
+
   }
   return std::string();
 }
 
 void RetrievePropertyOp::PerformCallback(SignedSettings::ReturnCode code,
                                          const std::string& value) {
   d_->OnSettingsOpCompleted(code, value);
 }
 
 StorePolicyOp::StorePolicyOp(em::PolicyFetchResponse* policy,
@@ skipping 162 matching lines @@
   sig.assign(sig_ptr, sig_ptr + policy_.policy_data_signature().length());
   service_->StartVerifyAttempt(policy_.policy_data(), sig, this);
 }
 
 void RetrievePolicyOp::PerformCallback(SignedSettings::ReturnCode code,
                                        const em::PolicyFetchResponse& value) {
   d_->OnSettingsOpCompleted(code, value);
 }
 
 }  // namespace chromeos