Enable GZIP for SingleSampleMediaSource

Issue: #4771

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=212623142

RELEASENOTES.md

@@ -113,6 +113,8 @@
   `MediaCodecRenderer`, and provide an (optional) `MediaCodecSelector` that
   falls back to less preferred decoders like `MediaCodec.createDecoderByType`
   ([#273](https://github.com/google/ExoPlayer/issues/273)).
+* Enable gzip for requests made by `SingleSampleMediaSource`
+  ([#4771](https://github.com/google/ExoPlayer/issues/4771)).
 * Fix bug reporting buffered position for multi-period windows, and add
   convenience methods `Player.getTotalBufferedDuration` and
   `Player.getContentBufferedDuration`

library/core/src/main/java/com/google/android/exoplayer2/source/SingleSampleMediaSource.java

@@ -287,7 +287,8 @@ public final class SingleSampleMediaSource extends BaseMediaSource {
     this.durationUs = durationUs;
     this.loadErrorHandlingPolicy = loadErrorHandlingPolicy;
     this.treatLoadErrorsAsEndOfStream = treatLoadErrorsAsEndOfStream;
-    dataSpec = new DataSpec(uri);
+    dataSpec =
+        new DataSpec(uri, DataSpec.FLAG_ALLOW_GZIP | DataSpec.FLAG_ALLOW_CACHING_UNKNOWN_LENGTH);
     timeline =
         new SinglePeriodTimeline(durationUs, /* isSeekable= */ true, /* isDynamic= */ false, tag);
   }