Simplify `DefaultMediaSourceFactory` instantiation in a test

There's no need to manually construct a 'default'
DefaultDataSource.Factory instance, we can just pass the `Context` to
`DefaultMediaSourceFactory` and let it construct the
`DefaultDataSource.Factory` internally.

PiperOrigin-RevId: 451155747

extensions/ima/src/androidTest/java/com/google/android/exoplayer2/ext/ima/ImaPlaybackTest.java

@@ -42,9 +42,7 @@ import com.google.android.exoplayer2.testutil.ExoHostedTest;
 import com.google.android.exoplayer2.testutil.HostActivity;
 import com.google.android.exoplayer2.testutil.TestUtil;
 import com.google.android.exoplayer2.trackselection.MappingTrackSelector;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSpec;
-import com.google.android.exoplayer2.upstream.DefaultDataSource;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Util;
 import java.util.ArrayList;
@@ -235,14 +233,13 @@ public final class ImaPlaybackTest {
     protected MediaSource buildSource(
         HostActivity host, DrmSessionManager drmSessionManager, FrameLayout overlayFrameLayout) {
       Context context = host.getApplicationContext();
-      DataSource.Factory dataSourceFactory = new DefaultDataSource.Factory(context);
       MediaSource contentMediaSource =
           new DefaultMediaSourceFactory(context).createMediaSource(MediaItem.fromUri(contentUri));
       return new AdsMediaSource(
           contentMediaSource,
           adTagDataSpec,
           /* adsId= */ adTagDataSpec.uri,
-          new DefaultMediaSourceFactory(dataSourceFactory),
+          new DefaultMediaSourceFactory(context),
           Assertions.checkNotNull(imaAdsLoader),
           () -> overlayFrameLayout);
     }