Remove garbageCollectionEnabled
Remove garbageCollectionEnabled

Chromium never compiles with Cocoa GC turned on and this function was left
from Webkit which had a real check for GC, now this function just returns false
so we can remove it.

Review URL: https://chromiumcodereview.appspot.com/14829002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@149629 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