Add device policy to disallow shutdown

chrome/browser/chromeos/policy/proto/chrome_device_policy.proto

Index: chrome/browser/chromeos/policy/proto/chrome_device_policy.proto
diff --git a/chrome/browser/chromeos/policy/proto/chrome_device_policy.proto b/chrome/browser/chromeos/policy/proto/chrome_device_policy.proto
index f5c1a4cd9b669076f92b61343f8bb82b52c28458..b08440bb29adb5201f543b4c8acbc4f3aa99a83e 100644
--- a/chrome/browser/chromeos/policy/proto/chrome_device_policy.proto
+++ b/chrome/browser/chromeos/policy/proto/chrome_device_policy.proto
@@ -583,6 +583,13 @@ message SAMLSettingsProto {
   optional bool transfer_saml_cookies = 1;
 }
 
+message ShutdownIsRebootProto {
+  // Determines whether the device may be shut down. If this flag is set to true

[bartfab (slow), 2014/12/08 16:49:44]

Nit: s/true/true,/

[cschuet (SLOW), 2014/12/08 18:57:04]

Done.

+  // shutdown is forbidden and UI elements trigger a device reboot instead of a
+  // power off. This policy controls shut down via the UI only.

[bartfab (slow), 2014/12/08 16:49:44]

Nit: s/shut down/shutdown/

[cschuet (SLOW), 2014/12/08 18:57:04]

Done.

+  optional bool shutdown_is_reboot = 1 [default = false];
+}
+
 message ChromeDeviceSettingsProto {
   optional DevicePolicyRefreshRateProto device_policy_refresh_rate = 1;
   optional UserWhitelistProto user_whitelist = 2;
@@ -617,4 +624,5 @@ message ChromeDeviceSettingsProto {
   optional AutoCleanupSettigsProto auto_clean_up_settings = 31;
   optional SystemSettingsProto system_settings = 32;
   optional SAMLSettingsProto saml_settings = 33;
+  optional ShutdownIsRebootProto shutdown_is_reboot = 34;
 }