Fix presentationDelay being set to NaN.

In the DASH parser, if there was no suggestedPresentationDelay and
ignoreMinBufferTime was set to true, the parser would set the
presentationDelay to NaN. This was because Math.max() will return NaN
if undefined is passed into it.
This changes minBufferTime to default to 0, if ignoreMinBufferTime is
true.

Fixes #2015

Change-Id: I8fc61706a04d14fd729e2185ce993a8bc87e48e5

lib/dash/dash_parser.js

@@ -509,7 +509,7 @@ shaka.dash.DashParser.prototype.processManifest_ =
       manifestBaseUris, uris);
 
   let ignoreMinBufferTime = this.config_.dash.ignoreMinBufferTime;
-  let minBufferTime;
+  let minBufferTime = 0;
   if (!ignoreMinBufferTime) {
     minBufferTime =
       XmlUtils.parseAttr(mpd, 'minBufferTime', XmlUtils.parseDuration);

test/dash/dash_parser_manifest_unit.js

@@ -1215,4 +1215,33 @@ describe('DashParser Manifest', function() {
     const minBufferTime = manifest.minBufferTime;
     expect(minBufferTime).toEqual(75);
   });
+
+  it('does not set presentationDelay to NaN', async () => {
+    // NOTE: This is a regression test for #2015. It ensures that, if
+    // ignoreMinBufferTime is true and there is no suggestedPresentationDelay,
+    // we do not erroneously set presentationDelay to NaN.
+    const manifestText = [
+      '<MPD minBufferTime="PT75S">',
+      '  <Period id="1" duration="PT30S">',
+      '    <AdaptationSet id="1" mimeType="video/mp4">',
+      '      <Representation id="video-sd" width="640" height="480">',
+      '        <BaseURL>v-sd.mp4</BaseURL>',
+      '        <SegmentBase indexRange="100-200" />',
+      '      </Representation>',
+      '    </AdaptationSet>',
+      '  </Period>',
+      '</MPD>',
+    ].join('\n');
+
+    fakeNetEngine.setResponseText('dummy://foo', manifestText);
+    const config = shaka.util.PlayerConfiguration.createDefault().manifest;
+    config.dash.ignoreMinBufferTime = true;
+    parser.configure(config);
+
+    const manifest = await parser.start('dummy://foo', playerInterface);
+    const presentationTimeline = manifest.presentationTimeline;
+    const presentationDelay = presentationTimeline.getDelay();
+    expect(presentationDelay).not.toBeNaN();
+    expect(presentationDelay).toBe(config.dash.defaultPresentationDelay);
+  });
 });