NuPlayerRenderer: stop feeding AudioSink when paused.

NuPlayerDriver: current position is updated only in running state.

Bug: 17141882
Change-Id: Ia88551cc29ef8f0e7ef0600a214feb5633389b6e
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerDriver.cpp b/media/libmediaplayerservice/nuplayer/NuPlayerDriver.cpp
index c4bbcdf..2423f5f 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerDriver.cpp
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerDriver.cpp
@@ -560,8 +560,10 @@
 
 void NuPlayerDriver::notifyPosition(int64_t positionUs) {
     Mutex::Autolock autoLock(mLock);
-    mPositionUs = positionUs;
-    mNotifyTimeRealUs = ALooper::GetNowUs();
+    if (isPlaying()) {
+        mPositionUs = positionUs;
+        mNotifyTimeRealUs = ALooper::GetNowUs();
+    }
 }
 
 void NuPlayerDriver::notifySeekComplete() {