Add MediaRouter2 method to show the SystemUI output switcher

Change the way to invoke media output switcher from an intent action
handled by SystemUI to a platform api that validate the calling package
name through the binder call.

Bug: 258532462
Test: Using androidx sample app.
Change-Id: I75e0856c18b3caed5ef0ebc9a057290c9a79e1d3

core/api/current.txt

@@ -24035,6 +24035,7 @@ package android.media {
     method public void registerTransferCallback(@NonNull java.util.concurrent.Executor, @NonNull android.media.MediaRouter2.TransferCallback);
     method public void setOnGetControllerHintsListener(@Nullable android.media.MediaRouter2.OnGetControllerHintsListener);
     method public void setRouteListingPreference(@Nullable android.media.RouteListingPreference);
+    method public void showSystemOutputSwitcher();
     method public void stop();
     method public void transferTo(@NonNull android.media.MediaRoute2Info);
     method public void unregisterControllerCallback(@NonNull android.media.MediaRouter2.ControllerCallback);

media/java/android/media/IMediaRouterService.aidl

@@ -94,4 +94,5 @@ interface IMediaRouterService {
     void setSessionVolumeWithManager(IMediaRouter2Manager manager, int requestId,
             String sessionId, int volume);
     void releaseSessionWithManager(IMediaRouter2Manager manager, int requestId, String sessionId);
+    void showMediaOutputSwitcher(String packageName);
 }

media/java/android/media/MediaRouter2.java

@@ -460,6 +460,19 @@ public final class MediaRouter2 {
         }
     }
 
+    /**
+     * Shows the system UI output switcher.
+     */
+    public void showSystemOutputSwitcher() {
+        synchronized (mLock) {
+            try {
+                mMediaRouterService.showMediaOutputSwitcher(mPackageName);
+            } catch (RemoteException ex) {
+                ex.rethrowFromSystemServer();
+            }
+        }
+    }
+
     /**
      * Sets the {@link RouteListingPreference} of the app associated to this media router.
      *

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

@@ -69,6 +69,7 @@ import com.android.internal.util.DumpUtils;
 import com.android.server.LocalServices;
 import com.android.server.Watchdog;
 import com.android.server.pm.UserManagerInternal;
+import com.android.server.statusbar.StatusBarManagerInternal;
 
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
@@ -245,6 +246,24 @@ public final class MediaRouterService extends IMediaRouterService.Stub
         }
     }
 
+    // Binder call
+    @Override
+    public void showMediaOutputSwitcher(String packageName) {
+        if (!validatePackageName(Binder.getCallingUid(), packageName)) {
+            throw new SecurityException("packageName must match the calling identity");
+        }
+        final long token = Binder.clearCallingIdentity();
+        try {
+            synchronized (mLock) {
+                StatusBarManagerInternal statusBar =
+                        LocalServices.getService(StatusBarManagerInternal.class);
+                statusBar.showMediaOutputSwitcher(packageName);
+            }
+        } finally {
+            Binder.restoreCallingIdentity(token);
+        }
+    }
+
     // Binder call
     @Override
     public MediaRouterClientState getState(IMediaRouterClient client) {