Add device policy definition for local accounts.

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 4b3a77aab8c7846eb9b1d0bc089d3926d01125b9..bb39555b99cb4ec9e70f6e30d6e1b63c3042eef6 100644
--- a/chrome/browser/policy/proto/chrome_device_policy.proto
+++ b/chrome/browser/policy/proto/chrome_device_policy.proto
@@ -220,6 +220,20 @@ message SystemTimezoneProto {
   optional string timezone = 1;
 }
 
+// Defines a local account.
+message LocalAccountDefinitionProto {
+  // String ID of the local account (e.g. user@example.com).
+  optional string id = 1;
+
+  // Human-readable account name for use on the login screen.
+  optional string name = 2;
+}
+
+message LocalAccountsProto {
+  // The list of local accounts that are available on the device.
+  repeated LocalAccountDefinitionProto local_account = 1;
+}
+
 message ChromeDeviceSettingsProto {
   optional DevicePolicyRefreshRateProto device_policy_refresh_rate = 1;
   optional UserWhitelistProto user_whitelist = 2;
@@ -241,4 +255,5 @@ message ChromeDeviceSettingsProto {
   optional StartUpUrlsProto start_up_urls = 18;
   optional PinnedAppsProto pinned_apps = 19;
   optional SystemTimezoneProto system_timezone = 20;
+  optional LocalAccountsProto local_accounts = 21;
 }