NuPlayer: Do not recreate AudioTrack if not needed

On output format change from the decoder, check if a new audio
track is really needed. This prevents excessive track
creation/destruction during seeks.

Bug: 18817027
Change-Id: I4290dcb90cb35bc1303b025e162f6b813d49a05b
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.h b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.h
index 406c64c..caa2bb3 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.h
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.h
@@ -180,6 +180,16 @@
     bool mAudioOffloadTornDown;
     audio_offload_info_t mCurrentOffloadInfo;
 
+    struct PcmInfo {
+        audio_channel_mask_t mChannelMask;
+        audio_output_flags_t mFlags;
+        audio_format_t mFormat;
+        int32_t mNumChannels;
+        int32_t mSampleRate;
+    };
+    PcmInfo mCurrentPcmInfo;
+    static const PcmInfo AUDIO_PCMINFO_INITIALIZER;
+
     int32_t mTotalBuffersQueued;
     int32_t mLastAudioBufferDrained;