Whitelist some debug commands in KioskNext

Allow a few debug commands in KioskNext when --ash-debug-shortcuts is
on the command line.

Bug: 932054
Change-Id: Id27b9abe9ff6901355d512b6439785751399ec7b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1542782
Auto-Submit: Michael Giuffrida <michaelpg@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#645384}

ash/accelerators/accelerator_table.cc

@@ -375,6 +375,9 @@ const size_t kActionsKeepingMenuOpenLength =
 const AcceleratorAction kActionsAllowedForKioskNextShell[] = {
     BRIGHTNESS_DOWN,
     BRIGHTNESS_UP,
+    DEBUG_TOGGLE_SHOW_DEBUG_BORDERS,
+    DEBUG_TOGGLE_SHOW_FPS_COUNTER,
+    DEBUG_TOGGLE_SHOW_PAINT_RECTS,
     KEYBOARD_BRIGHTNESS_DOWN,
     KEYBOARD_BRIGHTNESS_UP,
     MEDIA_NEXT_TRACK,