Fix download cancellation

Issue: #4403

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=201525284

RELEASENOTES.md

@@ -16,6 +16,8 @@
   ([#3906](https://github.com/google/ExoPlayer/issues/3906)).
 * Fix crash downloading HLS media playlists
   ([#4396](https://github.com/google/ExoPlayer/issues/4396)).
+* Fix a bug where download cancellation was ignored
+  ([#4403](https://github.com/google/ExoPlayer/issues/4403)).
 * Set `METADATA_KEY_TITLE` on media descriptions
   ([#4292](https://github.com/google/ExoPlayer/issues/4292)).
 * Allow apps to register custom MIME types

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

@@ -129,11 +129,11 @@ public final class CacheUtil {
         cache,
         new CacheDataSource(cache, upstream),
         new byte[DEFAULT_BUFFER_SIZE_BYTES],
-        null,
-        0,
+        /* priorityTaskManager= */ null,
+        /* priority= */ 0,
         counters,
-        null,
-        false);
+        isCanceled,
+        /* enableEOFException= */ false);
   }
 
   /**