Remove no-longer-true documentation

PiperOrigin-RevId: 224793600

library/core/src/main/java/com/google/android/exoplayer2/upstream/DataSpec.java

@@ -108,10 +108,7 @@ public final class DataSpec {
    * {@link DataSpec} is not intended to be used in conjunction with a cache.
    */
   public final @Nullable String key;
-  /**
-   * Request flags. Currently {@link #FLAG_ALLOW_GZIP} and
-   * {@link #FLAG_ALLOW_CACHING_UNKNOWN_LENGTH} are the only supported flags.
-   */
+  /** Request {@link Flags flags}. */
   public final @Flags int flags;
 
   /**

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheDataSource.java

@@ -42,10 +42,6 @@ import java.util.Map;
  * A {@link DataSource} that reads and writes a {@link Cache}. Requests are fulfilled from the cache
  * when possible. When data is not cached it is requested from an upstream {@link DataSource} and
  * written into the cache.
- *
- * <p>By default requests whose length can not be resolved are not cached. This is to prevent
- * caching of progressive live streams, which should usually not be cached. Caching of this kind of
- * requests can be enabled per request with {@link DataSpec#FLAG_ALLOW_CACHING_UNKNOWN_LENGTH}.
  */
 public final class CacheDataSource implements DataSource {