Switch the main demo app to use Guava's Preconditions

ExoPlayer's internal Assertions class will not be part of the stable
API.

PiperOrigin-RevId: 437008634

demos/main/src/main/java/androidx/media3/demo/main/DownloadTracker.java

@@ -15,8 +15,7 @@
  */
 package androidx.media3.demo.main;
 
-import static androidx.media3.common.util.Assertions.checkNotNull;
-import static androidx.media3.common.util.Assertions.checkStateNotNull;
+import static com.google.common.base.Preconditions.checkNotNull;
 
 import android.content.Context;
 import android.content.DialogInterface;
@@ -85,8 +84,7 @@ public class DownloadTracker {
   }
 
   public void addListener(Listener listener) {
-    checkNotNull(listener);
-    listeners.add(listener);
+    listeners.add(checkNotNull(listener));
   }
 
   public void removeListener(Listener listener) {
@@ -402,7 +400,7 @@ public class DownloadTracker {
       if (drmSessionException != null) {
         dialogHelper.onOfflineLicenseFetchedError(drmSessionException);
       } else {
-        dialogHelper.onOfflineLicenseFetched(downloadHelper, checkStateNotNull(keySetId));
+        dialogHelper.onOfflineLicenseFetched(downloadHelper, checkNotNull(keySetId));
       }
     }
   }

demos/main/src/main/java/androidx/media3/demo/main/IntentUtil.java

@@ -15,8 +15,9 @@
  */
 package androidx.media3.demo.main;
 
-import static androidx.media3.common.util.Assertions.checkNotNull;
-import static androidx.media3.common.util.Assertions.checkState;
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
 
 import android.content.Intent;
 import android.net.Uri;
@@ -26,7 +27,6 @@ import androidx.media3.common.MediaItem;
 import androidx.media3.common.MediaItem.ClippingConfiguration;
 import androidx.media3.common.MediaItem.SubtitleConfiguration;
 import androidx.media3.common.MediaMetadata;
-import androidx.media3.common.util.Assertions;
 import androidx.media3.common.util.Util;
 import com.google.common.collect.ImmutableList;
 import java.util.ArrayList;
@@ -86,7 +86,7 @@ public class IntentUtil {
 
   /** Populates the intent with the given list of {@link MediaItem media items}. */
   public static void addToIntent(List<MediaItem> mediaItems, Intent intent) {
-    Assertions.checkArgument(!mediaItems.isEmpty());
+    checkArgument(!mediaItems.isEmpty());
     if (mediaItems.size() == 1) {
       MediaItem mediaItem = mediaItems.get(0);
       MediaItem.LocalConfiguration localConfiguration = checkNotNull(mediaItem.localConfiguration);
@@ -241,7 +241,7 @@ public class IntentUtil {
         drmConfiguration.forcedSessionTrackTypes;
     if (!forcedDrmSessionTrackTypes.isEmpty()) {
       // Only video and audio together are supported.
-      Assertions.checkState(
+      checkState(
           forcedDrmSessionTrackTypes.size() == 2
               && forcedDrmSessionTrackTypes.contains(C.TRACK_TYPE_VIDEO)
               && forcedDrmSessionTrackTypes.contains(C.TRACK_TYPE_AUDIO));

demos/main/src/main/java/androidx/media3/demo/main/SampleChooserActivity.java

@@ -15,9 +15,9 @@
  */
 package androidx.media3.demo.main;
 
-import static androidx.media3.common.util.Assertions.checkArgument;
-import static androidx.media3.common.util.Assertions.checkNotNull;
-import static androidx.media3.common.util.Assertions.checkState;
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
 
 import android.content.Context;
 import android.content.Intent;