Added UMA metrics for MediaSourcePlayer and MediaCodecPlayer

media/base/android/media_source_player.h

Index: media/base/android/media_source_player.h
diff --git a/media/base/android/media_source_player.h b/media/base/android/media_source_player.h
index bfa3935c5d0ccfa890b7ea04b021a4e91616d96f..d7b67154a63df076da9edeebca8b8367a481d93c 100644
--- a/media/base/android/media_source_player.h
+++ b/media/base/android/media_source_player.h
@@ -23,6 +23,7 @@
 #include "media/base/android/media_decoder_job.h"
 #include "media/base/android/media_drm_bridge.h"
 #include "media/base/android/media_player_android.h"
+#include "media/base/android/media_statistics.h"
 #include "media/base/media_export.h"
 #include "media/base/time_delta_interpolator.h"
 
@@ -268,6 +269,10 @@ class MEDIA_EXPORT MediaSourcePlayer : public MediaPlayerAndroid,
   // Whether audio or video decoder is in the process of prerolling.
   bool prerolling_;
 
+  // Gathers and reports playback quality statistics to UMA.
+  // Use pointer to enable replacement of this object for tests.
+  scoped_ptr<MediaStatistics> media_stat_;
+
   // Weak pointer passed to media decoder jobs for callbacks.
   base::WeakPtr<MediaSourcePlayer> weak_this_;
   // NOTE: Weak pointers must be invalidated before all other member variables.