Propagate EXT-X-DATERANGE tags with media playlists

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=155062718

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylist.java

@@ -91,12 +91,14 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
   public final boolean hasProgramDateTime;
   public final Segment initializationSegment;
   public final List<Segment> segments;
+  public final List<String> dateRanges;
   public final long durationUs;
 
   public HlsMediaPlaylist(@PlaylistType int playlistType, String baseUri, long startOffsetUs,
       long startTimeUs, boolean hasDiscontinuitySequence, int discontinuitySequence,
       int mediaSequence, int version, long targetDurationUs, boolean hasEndTag,
-      boolean hasProgramDateTime, Segment initializationSegment, List<Segment> segments) {
+      boolean hasProgramDateTime, Segment initializationSegment, List<Segment> segments,
+      List<String> dateRanges) {
     super(baseUri);
     this.playlistType = playlistType;
     this.startTimeUs = startTimeUs;
@@ -117,6 +119,7 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
     }
     this.startOffsetUs = startOffsetUs == C.TIME_UNSET ? C.TIME_UNSET
         : startOffsetUs >= 0 ? startOffsetUs : durationUs + startOffsetUs;
+    this.dateRanges = Collections.unmodifiableList(dateRanges);
   }
 
   /**
@@ -155,7 +158,7 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
   public HlsMediaPlaylist copyWith(long startTimeUs, int discontinuitySequence) {
     return new HlsMediaPlaylist(playlistType, baseUri, startOffsetUs, startTimeUs, true,
         discontinuitySequence, mediaSequence, version, targetDurationUs, hasEndTag,
-        hasProgramDateTime, initializationSegment, segments);
+        hasProgramDateTime, initializationSegment, segments, dateRanges);
   }
 
   /**
@@ -170,7 +173,7 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
     }
     return new HlsMediaPlaylist(playlistType, baseUri, startOffsetUs, startTimeUs,
         hasDiscontinuitySequence, discontinuitySequence, mediaSequence, version, targetDurationUs,
-        true, hasProgramDateTime, initializationSegment, segments);
+        true, hasProgramDateTime, initializationSegment, segments, dateRanges);
   }
 
 }

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistParser.java

@@ -57,6 +57,7 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
   private static final String TAG_ENDLIST = "#EXT-X-ENDLIST";
   private static final String TAG_KEY = "#EXT-X-KEY";
   private static final String TAG_BYTERANGE = "#EXT-X-BYTERANGE";
+  private static final String TAG_DATERANGE = "#EXT-X-DATERANGE";
 
   private static final String TYPE_AUDIO = "AUDIO";
   private static final String TYPE_VIDEO = "VIDEO";
@@ -263,6 +264,7 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
     boolean hasEndTag = false;
     Segment initializationSegment = null;
     List<Segment> segments = new ArrayList<>();
+    List<String> dateRanges = new ArrayList<>();
 
     long segmentDurationUs = 0;
     boolean hasDiscontinuitySequence = false;
@@ -343,6 +345,8 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
               C.msToUs(Util.parseXsDateTime(line.substring(line.indexOf(':') + 1)));
           playlistStartTimeUs = programDatetimeUs - segmentStartTimeUs;
         }
+      } else if (line.startsWith(TAG_DATERANGE)) {
+        dateRanges.add(line);
       } else if (!line.startsWith("#")) {
         String segmentEncryptionIV;
         if (!isEncrypted) {
@@ -371,7 +375,8 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
     }
     return new HlsMediaPlaylist(playlistType, baseUri, startOffsetUs, playlistStartTimeUs,
         hasDiscontinuitySequence, playlistDiscontinuitySequence, mediaSequence, version,
-        targetDurationUs, hasEndTag, playlistStartTimeUs != 0, initializationSegment, segments);
+        targetDurationUs, hasEndTag, playlistStartTimeUs != 0, initializationSegment, segments,
+        dateRanges);
   }
 
   private static String parseStringAttr(String line, Pattern pattern) throws ParserException {