Use C APIs instead of C++ APIs for policy

The C++ APIs are going away.

Note: we use tid == 0 which is not supported yet by the C APIs,
do not submit this until that is added.

Change-Id: I0e90789e6c81c69f2544e899c52421ea5d1342be
diff --git a/include/media/AudioTrack.h b/include/media/AudioTrack.h
index 98b1f3e..639d6d2 100644
--- a/include/media/AudioTrack.h
+++ b/include/media/AudioTrack.h
@@ -28,6 +28,7 @@
 #include <utils/Errors.h>
 #include <binder/IInterface.h>
 #include <binder/IMemory.h>
+#include <cutils/sched_policy.h>
 #include <utils/threads.h>
 
 namespace android {
@@ -536,7 +537,7 @@
     status_t                mRestoreStatus;
     bool                    mIsTimed;
     int                     mPreviousPriority;          // before start()
-    int                     mPreviousSchedulingGroup;
+    SchedPolicy             mPreviousSchedulingGroup;
 };
 
 class TimedAudioTrack : public AudioTrack