NuPlayer: Enhance dumpsys statistics

Account for dropped output-frames (rather than input-frames)
in percentage dropped frames.
Print mime and component name for each active track

Change-Id: I3491d336c696d8ed0fd1503b80afe1df47c787c8
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerDecoderBase.h b/media/libmediaplayerservice/nuplayer/NuPlayerDecoderBase.h
index b52e7f7..8f030f0 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerDecoderBase.h
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerDecoderBase.h
@@ -42,9 +42,9 @@
     void signalResume(bool notifyComplete);
     void initiateShutdown();
 
-    virtual void getStats(
-            int64_t *mNumFramesTotal,
-            int64_t *mNumFramesDropped) const = 0;
+    virtual sp<AMessage> getStats() const {
+        return mStats;
+    }
 
     enum {
         kWhatInputDiscontinuity  = 'inDi',
@@ -76,6 +76,7 @@
 
     sp<AMessage> mNotify;
     int32_t mBufferGeneration;
+    sp<AMessage> mStats;
 
 private:
     enum {