Chop off even more unused bits from config.h.
Chop off even more unused bits from config.h.

HAVE_FUNC_USLEEP was only used in ContainerNode::setActive(), but that code
was deleted in https://codereview.chromium.org/13652013 .

BUG=none
TBR=dglazkov

Review URL: https://chromiumcodereview.appspot.com/14784004

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@149541 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs