base: Support setting thread priorities generically.
This patch supports setting priorities across platforms
at the PlatformThread level, by stashing thread id into the
thread handle on linux/android.
Since this adds more platform specific code, and #ifdefs
were starting to get unwieldy, all platform specific code
is moved into _platform.cc files, with the exception of the
'default' implementation, which stay in _posix.
BUG=170549
Review URL: https://chromiumcodereview.appspot.com/12741012
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@201202 0039d316-1c4b-4281-b951-d872f2087c98
CrOS-Libchrome-Original-Commit: a688c89c25dd5c966b112cd5dd8ef084698d363e
9 files changed