Move pref backing up flags from local state to device settings on ChromeOS.

chrome/browser/policy/proto/chrome_device_policy.proto

Index: chrome/browser/policy/proto/chrome_device_policy.proto
diff --git a/chrome/browser/policy/proto/chrome_device_policy.proto b/chrome/browser/policy/proto/chrome_device_policy.proto
index 4cd0058e2e88581aa56c61da63d60f31e83f217e..2ed793354d189fbae08b22e133599a77ec49abdc 100644
--- a/chrome/browser/policy/proto/chrome_device_policy.proto
+++ b/chrome/browser/policy/proto/chrome_device_policy.proto
@@ -245,6 +245,12 @@ message AllowRedeemChromeOsRegistrationOffersProto {
   optional bool allow_redeem_offers = 1 [default = true];
 }
 
+message StartUpFlagsProto {
+  // The list of flags to be applied to chrome on start-up (back up store for
+  // owner set flags in about:flags).
+  repeated string flags = 1;
+}
+
 message ChromeDeviceSettingsProto {
   optional DevicePolicyRefreshRateProto device_policy_refresh_rate = 1;
   optional UserWhitelistProto user_whitelist = 2;
@@ -268,4 +274,5 @@ message ChromeDeviceSettingsProto {
   optional SystemTimezoneProto system_timezone = 20;
   optional DeviceLocalAccountsProto device_local_accounts = 21;
   optional AllowRedeemChromeOsRegistrationOffersProto allow_redeem_offers = 22;
+  optional StartUpFlagsProto start_up_flags = 23;
 }