Use UserSwitchObserver to detect switches in the running user

The current implementation relies on listening for
Intent.ACTION_USER_SWITCHED, which can take more than 30
seconds to propagate, making UserSwitchObserver a more
reliable option.

Bug: 242188673
Test: atest mediaroutertest CtsMediaBetterTogetherTestCases
Test: Manually tested casting on secondary users.
Test: Pending CL to verify route availability on secondary users as part of the linked bug.
Change-Id: I67765a671bce590495b73ef7df6bf72ba3c9f03a
Merged-In: I67765a671bce590495b73ef7df6bf72ba3c9f03a

services/core/java/com/android/server/media/MediaRouter2ServiceImpl.java

@@ -601,10 +601,9 @@ class MediaRouter2ServiceImpl {
         }
     }
 
-    //TODO(b/136703681): Review this is handling multi-user properly.
+    // TODO(b/136703681): Review this is handling multi-user properly.
-    void switchUser() {
+    void switchUser(int userId) {
         synchronized (mLock) {
-            int userId = ActivityManager.getCurrentUser();
             if (mCurrentUserId != userId) {
                 final int oldUserId = mCurrentUserId;
                 mCurrentUserId = userId; // do this first

services/core/java/com/android/server/media/MediaRouterService.java

@@ -17,7 +17,9 @@
 package com.android.server.media;
 
 import android.annotation.NonNull;
+import android.annotation.RequiresPermission;
 import android.app.ActivityManager;
+import android.app.UserSwitchObserver;
 import android.bluetooth.BluetoothA2dp;
 import android.bluetooth.BluetoothDevice;
 import android.content.BroadcastReceiver;
@@ -217,18 +219,27 @@ public final class MediaRouterService extends IMediaRouterService.Stub
         context.registerReceiverAsUser(mReceiver, UserHandle.ALL, intentFilter, null, null);
     }
 
-    public void systemRunning() {
+    /**
-        IntentFilter filter = new IntentFilter(Intent.ACTION_USER_SWITCHED);
+     * Initializes the MediaRouter service.
-        mContext.registerReceiver(new BroadcastReceiver() {
+     *
-            @Override
+     * @throws RemoteException If an error occurs while registering the {@link UserSwitchObserver}.
-            public void onReceive(Context context, Intent intent) {
+     */
-                if (intent.getAction().equals(Intent.ACTION_USER_SWITCHED)) {
+    @RequiresPermission(
-                    switchUser();
+            anyOf = {
-                }
+                "android.permission.INTERACT_ACROSS_USERS",
-            }
+                "android.permission.INTERACT_ACROSS_USERS_FULL"
-        }, filter);
+            })
-
+    public void systemRunning() throws RemoteException {
-        switchUser();
+        ActivityManager.getService()
+                .registerUserSwitchObserver(
+                        new UserSwitchObserver() {
+                            @Override
+                            public void onUserSwitchComplete(int newUserId) {
+                                switchUser(newUserId);
+                            }
+                        },
+                        TAG);
+        switchUser(ActivityManager.getCurrentUser());
     }
 
     @Override
@@ -702,9 +713,8 @@ public final class MediaRouterService extends IMediaRouterService.Stub
         }
     }
 
-    void switchUser() {
+    void switchUser(int userId) {
         synchronized (mLock) {
-            int userId = ActivityManager.getCurrentUser();
             if (mCurrentUserId != userId) {
                 final int oldUserId = mCurrentUserId;
                 mCurrentUserId = userId; // do this first
@@ -721,7 +731,7 @@ public final class MediaRouterService extends IMediaRouterService.Stub
                 }
             }
         }
-        mService2.switchUser();
+        mService2.switchUser(userId);
     }
 
     void clientDied(ClientRecord clientRecord) {