Add update_over_cellular crosh command.

This patch adds a new update_over_cellular crosh command to enable,
disable and get the status of the update over cellular network user
preference.

BUG=chromium:213401
TEST=Ran the command in crosh with "enabled", "disabled" and no arguments.

Change-Id: Ie71a9538a94508a7cafff7b26bf3edd5e808066a
Reviewed-on: https://gerrit.chromium.org/gerrit/60721
Tested-by: Alex Deymo <deymo@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
diff --git a/crosh b/crosh
index 81d5606..a3f52dc 100755
--- a/crosh
+++ b/crosh
@@ -154,6 +154,10 @@
  tracepath [-n] <destination>[/port]
   Trace the path/route to a network host.
 
+ update_over_cellular [enable|disable]
+  Enables or disables the auto updates over cellular networks. Run without
+  arguments to see the current state.
+
  wpa_debug [<debug_level>] [--help] [--list_valid_level] [--reset]
   Set wpa_supplicant debugging level.
 
@@ -958,6 +962,30 @@
   fi
 }
 
+cmd_update_over_cellular() {
+  case "$1" in
+    "enable")
+      param="-update_over_cellular=yes"
+      ;;
+
+    "disable")
+      param="-update_over_cellular=no"
+      ;;
+
+    "")
+      param=""
+      ;;
+
+    *)
+      echo "Usage: update_over_cellular [enable|disable]
+  Enables or disables the auto updates over cellular networks. Run without
+  arguments to see the current state."
+      return 1
+      ;;
+  esac
+  /usr/bin/update_engine_client $param -show_update_over_cellular
+}
+
 cmd_tpcontrol() {
   /opt/google/touchpad/tpcontrol "$@"
 }