Base: Fix a race settin the running_ flag.

BUG=127931
TEST=green bots
TBR=jhawkins, willchan
Review URL: https://chromiumcodereview.appspot.com/10392188

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@138143 0039d316-1c4b-4281-b951-d872f2087c98

base/threading/thread.cc

@@ -161,11 +161,11 @@ void Thread::ThreadMain() {
     // Let's do this before signaling we are started.
     Init();
 
+    running_ = true;
     startup_data_->event.Signal();
     // startup_data_ can't be touched anymore since the starting thread is now
     // unlocked.
 
-    running_ = true;
     Run(message_loop_);
     running_ = false;