Rename enterprise policy proto fields from KIOSK to RETAIL.

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 501bee7247063a3b31ec989bae66586868a81023..0773f370256b687f2ed52f92a57bcaef024f3d9d 100644
--- a/chrome/browser/policy/proto/chrome_device_policy.proto
+++ b/chrome/browser/policy/proto/chrome_device_policy.proto
@@ -130,7 +130,7 @@ message ForcedLogoutTimeoutsProto {
 message ScreenSaverProto {
   // Specifies the extension ID which is to be used as a screen saver on the
   // login screen if no user activity is present. Only respected if the device
-  // is in KIOSK mode.
+  // is in RETAIL mode.
   optional string screen_saver_extension_id = 1;
 
   // Specifies the timeout before the screen saver is activated. If this field
@@ -162,7 +162,7 @@ message AutoUpdateSettingsProto {
 
 message StartUpUrlsProto {
   // Specifies the URLs to be loaded on login to the anonymous account used if
-  // the device is in KIOSK mode.
+  // the device is in RETAIL mode.
   repeated string start_up_urls = 1;
 }