Add AudioFlinger::PlaybackThread::Track::getTimestamp()

with a dummy implementation initially,
and use it in AudioFlinger::TrackHandle::getTimestamp()

Change-Id: I2da88fc52a135a7f0d9fd9538986e919dc8ccd3b
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index d1ab3c8..687217b 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -285,7 +285,7 @@
 
 status_t AudioFlinger::TrackHandle::getTimestamp(AudioTimestamp& timestamp)
 {
-    return INVALID_OPERATION;
+    return mTrack->getTimestamp(timestamp);
 }
 
 status_t AudioFlinger::TrackHandle::onTransact(
@@ -716,6 +716,17 @@
     }
 }
 
+status_t AudioFlinger::PlaybackThread::Track::getTimestamp(AudioTimestamp& timestamp)
+{
+    sp<ThreadBase> thread = mThread.promote();
+    if (thread == 0) {
+        return false;
+    }
+    Mutex::Autolock _l(thread->mLock);
+    PlaybackThread *playbackThread = (PlaybackThread *)thread.get();
+    return INVALID_OPERATION;
+}
+
 status_t AudioFlinger::PlaybackThread::Track::attachAuxEffect(int EffectId)
 {
     status_t status = DEAD_OBJECT;