Remove ThreadGlobalData.h

Only included in 3 places and none of them actually need it.

BUG=297477

Review URL: https://codereview.chromium.org/60083002

git-svn-id: svn://svn.chromium.org/blink/trunk@161345 bbb929c8-8fbe-4397-9dbb-9b2b20218538