fix(hls): Made HLS notify segments after fit

Previously, the HLS parser would notify the presentation timeline
of the segments in the manifest before fitting the segments.
The HLS parser will also sometimes remove segments from the end of
a VOD asset if they do not fit within the playlist duration.
This could sometimes cause the presentation timeline and MediaSource
to have different opinions on how long the VOD asset was, which could
lead to the seek bar looking like the presentation stopped before the
end.

Closes shaka-project#3733

Change-Id: I67fdc28a3f6eee158c9906359491fe6bb418e730

Author: theodab

lib/hls/hls_parser.js

@@ -534,6 +534,30 @@ shaka.hls.HlsParser = class {
       }
     }
 
+    // Now that the content has been fit, notify segments.
+    this.segmentsToNotifyByStream_ = [];
+    const streamsToNotify = [];
+    for (const variant of variants) {
+      for (const stream of [variant.video, variant.audio]) {
+        if (stream) {
+          streamsToNotify.push(stream);
+        }
+      }
+    }
+    await Promise.all(streamsToNotify.map(async (stream) => {
+      await stream.createSegmentIndex();
+    }));
+    for (const stream of streamsToNotify) {
+      this.segmentsToNotifyByStream_.push(stream.segmentIndex.references);
+    }
+    this.notifySegments_();
+
+    // This asserts that the live edge is being calculated from segment times.
+    // For VOD and event streams, this check should still pass.
+    goog.asserts.assert(
+        !this.presentationTimeline_.usingPresentationStartTime(),
+        'We should not be using the presentation start time in HLS!');
+
     this.manifest_ = {
       presentationTimeline: this.presentationTimeline_,
       variants,
@@ -1618,12 +1642,6 @@ shaka.hls.HlsParser = class {
     }
 
     this.notifySegments_();
-
-    // This asserts that the live edge is being calculated from segment times.
-    // For VOD and event streams, this check should still pass.
-    goog.asserts.assert(
-        !this.presentationTimeline_.usingPresentationStartTime(),
-        'We should not be using the presentation start time in HLS!');
   }
 
   /**
@@ -2014,9 +2032,6 @@ shaka.hls.HlsParser = class {
       }
     }
 
-    this.segmentsToNotifyByStream_.push(references);
-    this.notifySegments_();
-
     return references;
   }
 

test/hls/hls_parser_unit.js

@@ -1309,6 +1309,8 @@ describe('HlsParser', () => {
     // stream.
     const timeline = actual.presentationTimeline;
     expect(timeline.getDuration()).toBe(10);
+    expect(timeline.getSeekRangeStart()).toBe(0);
+    expect(timeline.getSeekRangeEnd()).toBe(10);
 
     expect(actual.textStreams.length).toBe(1);
     expect(actual.variants.length).toBe(1);