Revert "Remove SkThread.h from public API."

Too much depends on SkThread being in include/core in Chrome build.

This reverts commit b1aec17df6078115c797839c9646081ccba2bd09.

NOTREECHECKS=true
NOTRY=true
R=reed@google.com, mtklein@google.com
TBR=reed

BUG=skia:

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/303813003

git-svn-id: http://skia.googlecode.com/svn/trunk@14934 2bbb7eff-a529-9590-31e7-b0007b416f81
9 files changed