Previously the code relied upon global variables which could not be
modified if the code was running from ROM (or similarly a flash memory
which is not easily modified).
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9667 6f19259b-4bc3-4df7-8a09-765794883524
hhtian
xli24
jljusten
lgao4