diff --git a/services/core/java/com/android/server/media/MediaSession2Record.java b/services/core/java/com/android/server/media/MediaSession2Record.java
index a110e56..7af5c08 100644
--- a/services/core/java/com/android/server/media/MediaSession2Record.java
+++ b/services/core/java/com/android/server/media/MediaSession2Record.java
@@ -35,12 +35,11 @@
  * Keeps the record of {@link Session2Token} to help send command to the corresponding session.
  */
 // TODO(jaewan): Do not call service method directly -- introduce listener instead.
-public class MediaSession2Record implements MediaSessionRecordImpl {
+public class MediaSession2Record extends MediaSessionRecordImpl {
     private static final String TAG = "MediaSession2Record";
     private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
     private final Object mLock = new Object();
 
-    private final int mUniqueId;
     @GuardedBy("mLock")
     private final Session2Token mSessionToken;
     @GuardedBy("mLock")
@@ -64,13 +63,12 @@
             MediaSessionService service,
             Looper handlerLooper,
             int pid,
-            int policies,
-            int uniqueId) {
+            int policies) {
         // The lock is required to prevent `Controller2Callback` from using partially initialized
         // `MediaSession2Record.this`.
         synchronized (mLock) {
+            mUniqueId = sNextMediaSessionRecordId.getAndIncrement();
             mSessionToken = sessionToken;
-            mUniqueId = uniqueId;
             mService = service;
             mHandlerExecutor = new HandlerExecutor(new Handler(handlerLooper));
             mController = new MediaController2.Builder(service.getContext(), sessionToken)
@@ -101,13 +99,6 @@
     }
 
     @Override
-    public int getUniqueId() {
-        synchronized (mLock) {
-            return mUniqueId;
-        }
-    }
-
-    @Override
     public String getPackageName() {
         return mSessionToken.getPackageName();
     }
@@ -210,7 +201,7 @@
 
     @Override
     public void dump(PrintWriter pw, String prefix) {
-        pw.println(prefix + "uniqueId=" + mUniqueId);
+        pw.println(prefix + "uniqueId=" + getUniqueId());
         pw.println(prefix + "token=" + mSessionToken);
         pw.println(prefix + "controller=" + mController);
 
@@ -220,7 +211,7 @@
 
     @Override
     public String toString() {
-        return getPackageName() + "/" + mUniqueId + " (userId=" + getUserId() + ")";
+        return getPackageName() + "/" + getUniqueId() + " (userId=" + getUserId() + ")";
     }
 
     private class Controller2Callback extends MediaController2.ControllerCallback {
diff --git a/services/core/java/com/android/server/media/MediaSessionRecord.java b/services/core/java/com/android/server/media/MediaSessionRecord.java
index 1552704..a9a8272 100644
--- a/services/core/java/com/android/server/media/MediaSessionRecord.java
+++ b/services/core/java/com/android/server/media/MediaSessionRecord.java
@@ -96,7 +96,7 @@
  * MediaSession wrapper class instead.
  */
 // TODO(jaewan): Do not call service method directly -- introduce listener instead.
-public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionRecordImpl {
+public class MediaSessionRecord extends MediaSessionRecordImpl implements IBinder.DeathRecipient {
 
     /**
      * {@link android.media.session.MediaSession#setMediaButtonBroadcastReceiver(
@@ -173,7 +173,6 @@
     private final int mUserId;
     private final String mPackageName;
     private final String mTag;
-    private final int mUniqueId;
     private final Bundle mSessionInfo;
     private final ControllerStub mController;
     private final MediaSession.Token mSessionToken;
@@ -231,18 +230,17 @@
             String ownerPackageName,
             ISessionCallback cb,
             String tag,
-            int uniqueId,
             Bundle sessionInfo,
             MediaSessionService service,
             Looper handlerLooper,
             int policies)
             throws RemoteException {
+        mUniqueId = sNextMediaSessionRecordId.getAndIncrement();
         mOwnerPid = ownerPid;
         mOwnerUid = ownerUid;
         mUserId = userId;
         mPackageName = ownerPackageName;
         mTag = tag;
-        mUniqueId = uniqueId;
         mSessionInfo = sessionInfo;
         mController = new ControllerStub();
         mSessionToken = new MediaSession.Token(ownerUid, mController);
@@ -303,16 +301,6 @@
     }
 
     /**
-     * Get the unique id of this session record.
-     *
-     * @return a unique id of this session record.
-     */
-    @Override
-    public int getUniqueId() {
-        return mUniqueId;
-    }
-
-    /**
      * Get the info for this session.
      *
      * @return Info that identifies this session.
@@ -724,7 +712,7 @@
 
     @Override
     public String toString() {
-        return mPackageName + "/" + mTag + "/" + mUniqueId + " (userId=" + mUserId + ")";
+        return mPackageName + "/" + mTag + "/" + getUniqueId() + " (userId=" + mUserId + ")";
     }
 
     @Override
diff --git a/services/core/java/com/android/server/media/MediaSessionRecordImpl.java b/services/core/java/com/android/server/media/MediaSessionRecordImpl.java
index e53a2db..e4b2fad 100644
--- a/services/core/java/com/android/server/media/MediaSessionRecordImpl.java
+++ b/services/core/java/com/android/server/media/MediaSessionRecordImpl.java
@@ -25,39 +25,37 @@
 import com.android.server.media.MediaSessionPolicyProvider.SessionPolicy;
 
 import java.io.PrintWriter;
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * Common interfaces between {@link MediaSessionRecord} and {@link MediaSession2Record}.
  */
-public interface MediaSessionRecordImpl extends AutoCloseable {
+public abstract class MediaSessionRecordImpl {
 
-    /**
-     * Get the unique id of this session record.
-     *
-     * @return a unique id of this session record.
-     */
-    int getUniqueId();
+    static final AtomicInteger sNextMediaSessionRecordId = new AtomicInteger(1);
+    int mUniqueId;
 
     /**
      * Get the info for this session.
      *
      * @return Info that identifies this session.
      */
-    String getPackageName();
+    public abstract String getPackageName();
 
     /**
      * Get the UID this session was created for.
      *
      * @return The UID for this session.
      */
-    int getUid();
+    public abstract int getUid();
 
     /**
      * Get the user id this session was created for.
      *
      * @return The user id for this session.
      */
-    int getUserId();
+    public abstract int getUserId();
 
     /**
      * Get the {@link ForegroundServiceDelegationOptions} needed for notifying activity manager
@@ -66,7 +64,7 @@
      * @return the {@link ForegroundServiceDelegationOptions} needed for notifying the activity
      *     manager service with changes in the {@link PlaybackState} for this session.
      */
-    ForegroundServiceDelegationOptions getForegroundServiceDelegationOptions();
+    public abstract ForegroundServiceDelegationOptions getForegroundServiceDelegationOptions();
 
     /**
      * Check if this session has system priority and should receive media buttons before any other
@@ -74,7 +72,7 @@
      *
      * @return True if this is a system priority session, false otherwise
      */
-    boolean isSystemPriority();
+    public abstract boolean isSystemPriority();
 
     /**
      * Send a volume adjustment to the session owner. Direction must be one of
@@ -95,7 +93,7 @@
      * @param useSuggested True to use adjustSuggestedStreamVolumeForUid instead of
      *          adjustStreamVolumeForUid
      */
-    void adjustVolume(String packageName, String opPackageName, int pid, int uid,
+    public abstract void adjustVolume(String packageName, String opPackageName, int pid, int uid,
             boolean asSystemService, int direction, int flags, boolean useSuggested);
 
     /**
@@ -105,7 +103,7 @@
      * @return True if the session is active, false otherwise.
      */
     // TODO(jaewan): Find better naming, or remove this from the MediaSessionRecordImpl.
-    boolean isActive();
+    public abstract boolean isActive();
 
     /**
      * Check if the session's playback active state matches with the expectation. This always
@@ -115,7 +113,7 @@
      * @param expected True if playback is expected to be active. False otherwise.
      * @return True if the session's playback matches with the expectation. False otherwise.
      */
-    boolean checkPlaybackActiveState(boolean expected);
+    public abstract boolean checkPlaybackActiveState(boolean expected);
 
     /**
      * Check whether the playback type is local or remote.
@@ -128,7 +126,7 @@
      *
      * @return {@code true} if the playback is local. {@code false} if the playback is remote.
      */
-    boolean isPlaybackTypeLocal();
+    public abstract boolean isPlaybackTypeLocal();
 
     /**
      * Sends media button.
@@ -145,27 +143,27 @@
      * @return {@code true} if the attempt to send media button was successfully.
      *         {@code false} otherwise.
      */
-    boolean sendMediaButton(String packageName, int pid, int uid, boolean asSystemService,
-            KeyEvent ke, int sequenceId, ResultReceiver cb);
+    public abstract boolean sendMediaButton(String packageName, int pid, int uid,
+            boolean asSystemService, KeyEvent ke, int sequenceId, ResultReceiver cb);
 
     /**
      * Returns whether the media session can handle volume key events.
      *
      * @return True if this media session can handle volume key events, false otherwise.
      */
-    boolean canHandleVolumeKey();
+    public abstract boolean canHandleVolumeKey();
 
     /**
      * Get session policies from custom policy provider set when MediaSessionRecord is instantiated.
      * If custom policy does not exist, will return null.
      */
     @SessionPolicy
-    int getSessionPolicies();
+    public abstract int getSessionPolicies();
 
     /**
      * Overwrite session policies that have been set when MediaSessionRecord is instantiated.
      */
-    void setSessionPolicies(@SessionPolicy int policies);
+    public abstract void setSessionPolicies(@SessionPolicy int policies);
 
     /**
      * Dumps internal state
@@ -173,16 +171,37 @@
      * @param pw print writer
      * @param prefix prefix
      */
-    void dump(PrintWriter pw, String prefix);
+    public abstract void dump(PrintWriter pw, String prefix);
 
     /**
-     * Override {@link AutoCloseable#close} to tell it not to throw exception.
+     * Similar to {@link AutoCloseable#close} without throwing an exception.
      */
-    @Override
-    void close();
+    public abstract void close();
+
+    /**
+     * Get the unique id of this session record.
+     *
+     * @return a unique id of this session record.
+     */
+    public int getUniqueId() {
+        return mUniqueId;
+    }
 
     /**
      * Returns whether {@link #close()} is called before.
      */
-    boolean isClosed();
+    public abstract boolean isClosed();
+
+    @Override
+    public final boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || !(o instanceof MediaSessionRecordImpl)) return false;
+        MediaSessionRecordImpl that = (MediaSessionRecordImpl) o;
+        return mUniqueId == that.mUniqueId;
+    }
+
+    @Override
+    public final int hashCode() {
+        return Objects.hash(mUniqueId);
+    }
 }
diff --git a/services/core/java/com/android/server/media/MediaSessionService.java b/services/core/java/com/android/server/media/MediaSessionService.java
index 09c6dc0e6..4285174 100644
--- a/services/core/java/com/android/server/media/MediaSessionService.java
+++ b/services/core/java/com/android/server/media/MediaSessionService.java
@@ -106,7 +106,6 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
-import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * System implementation of MediaSessionManager
@@ -172,8 +171,6 @@
     /* Maps uid with all user engaging session tokens associated to it */
     private final SparseArray<Set<MediaSession.Token>> mUserEngagingSessions = new SparseArray<>();
 
-    private final AtomicInteger mNextMediaSessionRecordId = new AtomicInteger(1);
-
     // The FullUserRecord of the current users. (i.e. The foreground user that isn't a profile)
     // It's always not null after the MediaSessionService is started.
     private FullUserRecord mCurrentFullUserRecord;
@@ -212,8 +209,7 @@
                                     MediaSessionService.this,
                                     mRecordThread.getLooper(),
                                     pid,
-                                    /* policies= */ 0,
-                                    /* uniqueId= */ mNextMediaSessionRecordId.getAndIncrement());
+                                    /* policies= */ 0);
                     synchronized (mLock) {
                         FullUserRecord user = getFullUserRecordLocked(record.getUserId());
                         if (user != null) {
@@ -824,7 +820,6 @@
                                 callerPackageName,
                                 cb,
                                 tag,
-                                /* uniqueId= */ mNextMediaSessionRecordId.getAndIncrement(),
                                 sessionInfo,
                                 this,
                                 mRecordThread.getLooper(),