Fix resolution menu restoration

If the resolution menu sees audio-only content, it should be hidden.
But it should come back as soon as the audio-video content is seen.

This came up during work on #997 and #382

Change-Id: I3297847c905c867bcdd14cf7e525a408890a273a

test/test/util/test_scheme.js

@@ -162,6 +162,20 @@ shaka.test.TestScheme.DATA = {
   // 'sintel_short_periods' : Generated by createManifests().
   // 'sintel_multi_lingual_multi_res' : Generated by createManifests().
 
+  'sintel_audio_only': {
+    audio: {
+      initSegmentUri: '/base/test/test/assets/sintel-audio-init.mp4',
+      mdhdOffset: 0x1b6,
+      segmentUri: '/base/test/test/assets/sintel-audio-segment.mp4',
+      tfdtOffset: 0x3c,
+      segmentDuration: 10.005,
+      presentationTimeOffset: 0,
+      mimeType: 'audio/mp4',
+      codecs: 'mp4a.40.2',
+    },
+    duration: 30,
+  },
+
   'sintel_no_text': {
     video: {
       initSegmentUri: '/base/test/test/assets/sintel-video-init.mp4',
@@ -463,9 +477,12 @@ shaka.test.TestScheme.createManifests = function(shaka, suffix) {
     let gen = new windowShaka.test.ManifestGenerator(shaka)
         .setPresentationDuration(data.duration)
         .addPeriod(/* startTime= */ 0)
-        .addVariant(0)
-          .addVideo(1);
-    addStreamInfo(gen, data, ContentType.VIDEO, name);
+        .addVariant(0);
+
+    if (data[ContentType.VIDEO]) {
+      gen.addVideo(1);
+      addStreamInfo(gen, data, ContentType.VIDEO, name);
+    }
     if (data[ContentType.AUDIO]) {
       gen.addAudio(2);
       addStreamInfo(gen, data, ContentType.AUDIO, name);

test/ui/ui_integration.js

@@ -331,7 +331,6 @@ describe('UI', () => {
 
       updateResolutionButtonsAndMap();
 
-
       oldResolutionTrack = findTrackWithHeight(tracks, oldResolution);
     });
 
@@ -435,6 +434,21 @@ describe('UI', () => {
       expect(isChosen).not.toBe(null);
     });
 
+    it('restores the resolutions menu after audio-only playback', async () => {
+      /** @type {HTMLElement} */
+      const resolutionButton = getElementByClassName(
+          'shaka-resolution-button', videoContainer);
+
+      // Load an audio-only clip.  The menu should be hidden.
+      await player.load('test:sintel_audio_only_compiled');
+      expect(player.isAudioOnly()).toBe(true);
+      expect(resolutionButton.classList.contains('shaka-hidden')).toBe(true);
+
+      // Load an audio-video clip.  The menu should be visible again.
+      await player.load('test:sintel_multi_lingual_multi_res_compiled');
+      expect(player.isAudioOnly()).toBe(false);
+      expect(resolutionButton.classList.contains('shaka-hidden')).toBe(false);
+    });
 
     /**
      * @return {Element}

ui/resolution_selection.js

@@ -142,12 +142,17 @@ shaka.ui.ResolutionSelection = class extends shaka.ui.Element {
   /** @private */
   updateResolutionSelection_() {
     let tracks = this.player.getVariantTracks();
-    // Hide resolution menu and button for audio-only content.
+
+    // Hide resolution menu and button for audio-only content and src= content
+    // without resolution information.
     if (tracks.length && !tracks[0].height) {
       shaka.ui.Utils.setDisplay(this.resolutionMenu_, false);
       shaka.ui.Utils.setDisplay(this.resolutionButton_, false);
       return;
     }
+    // Otherwise, restore it.
+    shaka.ui.Utils.setDisplay(this.resolutionButton_, true);
+
     tracks.sort(function(t1, t2) {
       return t1.height - t2.height;
     });