Change the androidx MediaRouter logging tag

To disambiguate from the platform MediaRouter.

Bug: 205124386
Change-Id: Ib619f2c10630596cc4e5edda3206ce088d91acdc
Test: N/A
diff --git a/mediarouter/mediarouter/src/main/java/androidx/mediarouter/media/MediaRouter.java b/mediarouter/mediarouter/src/main/java/androidx/mediarouter/media/MediaRouter.java
index 36251c0..e182fd9 100644
--- a/mediarouter/mediarouter/src/main/java/androidx/mediarouter/media/MediaRouter.java
+++ b/mediarouter/mediarouter/src/main/java/androidx/mediarouter/media/MediaRouter.java
@@ -82,7 +82,8 @@
  */
 // TODO: Add the javadoc for manifest requirements about 'Package visibility' in Android 11
 public final class MediaRouter {
-    static final String TAG = "MediaRouter";
+    // The "Ax" prefix disambiguates from the platform's MediaRouter.
+    static final String TAG = "AxMediaRouter";
     static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
 
     @IntDef({