Support standard keyboard keys emulated by the braille drivers.

This plumbs through keys like backspace and enter and arrow keys.
It also provides Unicode characters for displays with query keyboards etc.

BUG=310285
R=dtseng@chromium.org, kalman@chromium.org

Review URL: https://codereview.chromium.org/297833015

git-svn-id: http://src.chromium.org/svn/trunk/src/build@273171 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

linux/system.gyp

@@ -746,7 +746,6 @@
                      '--link-directly=<(linux_link_libbrlapi)',
                      'brlapi_getHandleSize',
                      'brlapi_error_location',
-                     'brlapi_expandKeyCode',
                      'brlapi_strerror',
                      'brlapi__acceptKeys',
                      'brlapi__openConnection',