Remove --enable-firewall-hole-punching flag, default to enabled.

chrome/app/chromeos_strings.grdp

Index: chrome/app/chromeos_strings.grdp
diff --git a/chrome/app/chromeos_strings.grdp b/chrome/app/chromeos_strings.grdp
index 6c8a34a3dc17c0d8f160d3819f2bb50d3079ad60..096d7037ea212e69fbd97aa066dbbecbb111aad2 100644
--- a/chrome/app/chromeos_strings.grdp
+++ b/chrome/app/chromeos_strings.grdp
@@ -6321,12 +6321,6 @@ All users must sign out to continue.
   <message name="IDS_OPTIONS_RESOLVE_TIMEZONE_BY_GEOLOCATION_DESCRIPTION" desc="Label for checkbox to allow automatic timezone update by user geolocation.">
     Set time zone automatically using your location
   </message>
-  <message name="IDS_FLAGS_ENABLE_FIREWALL_HOLE_PUNCHING_NAME" desc="Name of the option to enable punching holes in the Chrome OS firewall.">
-    Enable firewall hole punching.
-  </message>
-  <message name="IDS_FLAGS_ENABLE_FIREWALL_HOLE_PUNCHING_DESCRIPTION" desc="Description of the option to enable punching holes in the Chrome OS firewall.">
-    Enable punching holes in the Chrome OS firewall for Chrome Apps that open a TCP/IP server socket or UDP socket.
-  </message>
   <message name="IDS_FILE_SYSTEM_REQUEST_FILE_SYSTEM_DIALOG_TITLE" desc="Title of a prompt dialog for granting permissions to a volume (eg. USB drive, SD card, MTP device) with the specified name.">
     Permission requested
   </message>