Use ContextCompat.getMainExecutor when calling MediaBrowser methods

Replacing remaining usage of MoreExecutors.directExecutor. This allows the service to be switched to run in another process and the app still works the same as if it is running in the same process.

Issue: androidx/media#100
PiperOrigin-RevId: 471547177

demos/session/src/main/java/androidx/media3/demo/session/MainActivity.kt

@@ -34,7 +34,6 @@ import androidx.media3.session.MediaBrowser
 import androidx.media3.session.SessionToken
 import com.google.android.material.floatingactionbutton.ExtendedFloatingActionButton
 import com.google.common.util.concurrent.ListenableFuture
-import com.google.common.util.concurrent.MoreExecutors
 
 class MainActivity : AppCompatActivity() {
   private lateinit var browserFuture: ListenableFuture<MediaBrowser>
@@ -105,7 +104,7 @@ class MainActivity : AppCompatActivity() {
           SessionToken(this, ComponentName(this, PlaybackService::class.java))
         )
         .buildAsync()
-    browserFuture.addListener({ pushRoot() }, MoreExecutors.directExecutor())
+    browserFuture.addListener({ pushRoot() }, ContextCompat.getMainExecutor(this))
   }
 
   private fun releaseBrowser() {
@@ -132,7 +131,7 @@ class MainActivity : AppCompatActivity() {
         subItemMediaList.addAll(children)
         mediaListAdapter.notifyDataSetChanged()
       },
-      MoreExecutors.directExecutor()
+      ContextCompat.getMainExecutor(this)
     )
   }
 

demos/session/src/main/java/androidx/media3/demo/session/PlayableFolderActivity.kt

@@ -38,7 +38,6 @@ import com.google.android.material.floatingactionbutton.ExtendedFloatingActionBu
 import com.google.android.material.snackbar.BaseTransientBottomBar
 import com.google.android.material.snackbar.Snackbar
 import com.google.common.util.concurrent.ListenableFuture
-import com.google.common.util.concurrent.MoreExecutors
 
 class PlayableFolderActivity : AppCompatActivity() {
   private lateinit var browserFuture: ListenableFuture<MediaBrowser>
@@ -132,7 +131,7 @@ class PlayableFolderActivity : AppCompatActivity() {
           SessionToken(this, ComponentName(this, PlaybackService::class.java))
         )
         .buildAsync()
-    browserFuture.addListener({ displayFolder() }, MoreExecutors.directExecutor())
+    browserFuture.addListener({ displayFolder() }, ContextCompat.getMainExecutor(this))
   }
 
   private fun releaseBrowser() {