Add two public methods for Scheduler

Add methods threads() and rootThreadId() for Scheduler to expose threads
info to outside world.

Signed-off-by: Xiangdong Lin <xiangdongl@mozy.com>
Change-Id: Ifc51a132433c0c120ee45d7b16bfa0ac6592a08a
Reviewed-on: https://gerrit.dechocorp.com/26665
Reviewed-by: Andrew Skowronski <andrews@mozy.com>
Reviewed-by: Kevin Cai <kcai@vmware.com>

mordor/scheduler.h

@@ -144,6 +144,12 @@ class Scheduler : public boost::noncopyable
     /// Change the number of threads in this scheduler
     void threadCount(size_t threads);
 
+    const std::vector<boost::shared_ptr<Thread> >& threads() const
+    {
+        return m_threads;
+    }
+
+    tid_t rootThreadId() const { return m_rootThread; }
 protected:
     /// Derived classes can query stopping() to see if the Scheduler is trying
     /// to stop, and should return from the idle Fiber as soon as possible.