Remove more dead Chromium code from WTF
https://bugs.webkit.org/show_bug.cgi?id=114037

Reviewed by Allan Sandfeld Jensen.

* wtf/CurrentTime.cpp:
(WTF):
* wtf/DisallowCType.h:
* wtf/ExportMacros.h:
* wtf/MainThread.cpp:
* wtf/Platform.h:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@147755 268f45cc-cd09-0410-ab3c-d52691b4dbfc