NuPlayer: make MediaClock a player-wide resource.

Test: compiles
Bug: 65204641
Change-Id: I7e58abd508b29c222cdb9fd2e60563cf5735a444
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerDriver.h b/media/libmediaplayerservice/nuplayer/NuPlayerDriver.h
index c5ddcb0..22e397f 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerDriver.h
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerDriver.h
@@ -22,6 +22,7 @@
 namespace android {
 
 struct ALooper;
+struct MediaClock;
 struct NuPlayer;
 
 struct NuPlayerDriver : public MediaPlayerInterface {
@@ -127,6 +128,7 @@
     // <<<
 
     sp<ALooper> mLooper;
+    const sp<MediaClock> mMediaClock;
     const sp<NuPlayer> mPlayer;
     sp<AudioSink> mAudioSink;
     uint32_t mPlayerFlags;