Linux: Set thread name on ShutdownDetector thread.
Linux: Set thread name on ShutdownDetector thread.

BUG=none
TEST=enable the posix PlatformThread::SetName, cat /proc/<chromepid>/task/*/stat

Review URL: http://codereview.chromium.org/3035019

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@53496 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser