media: Make MediaKeys ref-counted.

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 7e4d706c38125941f48873606c582f889bc1557c..e93fe15e32ba62675728c6321f3bb5d1af71495b 100644
--- a/media/base/android/media_source_player.h
+++ b/media/base/android/media_source_player.h
@@ -63,7 +63,7 @@ class MEDIA_EXPORT MediaSourcePlayer : public MediaPlayerAndroid,
   bool CanSeekForward() override;
   bool CanSeekBackward() override;
   bool IsPlayerReady() override;
-  void SetCdm(BrowserCdm* cdm) override;
+  void SetCdm(const scoped_refptr<MediaKeys>& cdm) override;
 
   // DemuxerAndroidClient implementation.
   void OnDemuxerConfigsAvailable(const DemuxerConfigs& params) override;
@@ -245,6 +245,9 @@ class MEDIA_EXPORT MediaSourcePlayer : public MediaPlayerAndroid,
   // elapses.
   base::CancelableClosure decoder_starvation_callback_;
 
+  // Holds a ref-count to the CDM to keep |drm_bridge_| valid.
+  scoped_refptr<MediaKeys> cdm_;
+
   MediaDrmBridge* drm_bridge_;
   int cdm_registration_id_;