Enables terminal font resizing for the numeric +/- keys.
Enables terminal font resizing for the numeric +/- keys.

Change-Id: Icab0b34b2837fcb18783fbdb3db84408819c703b
Reviewed-on: https://chromium-review.googlesource.com/270805
Reviewed-by: Rob Ginda <4419ac4e35d191308e944202d542b192188656d1@chromium.org>
Tested-by: Rob Ginda <4419ac4e35d191308e944202d542b192188656d1@chromium.org>

chromium/hterm,chromium/hterm,chromium/hterm,chromium/hterm