Remove pthread_getspecific_direct code.
Remove pthread_getspecific_direct code.

We were never using and half-removed it already. It also relies on internal
APIs and an internal header where OS X's libc effectively special-cases their
WebKit.

BUG=none

Review URL: https://codereview.chromium.org/29693006

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@160244 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