addExternalCaptions can now be called more than once.

Multiple calls to DashVideoSource.addExternalCaptions will each
add a caption source to the object.  Added unit and integration
tests for this.

Change-Id: I387d285b5d11aa345b3abefab05d633194863030

lib/player/dash_video_source.js

@@ -65,14 +65,14 @@ shaka.player.DashVideoSource =
   /** @private {?shaka.player.DashVideoSource.ContentProtectionCallback} */
   this.interpretContentProtection_ = interpretContentProtection;
 
-  /** @private {?string} */
-  this.captionsUrl_ = null;
+  /** @private {!Array.<string>} */
+  this.captionsUrl_ = [];
 
-  /** @private {string} */
-  this.captionsLang_ = '';
+  /** @private {!Array.<string>} */
+  this.captionsLang_ = [];
 
-  /** @private {string} */
-  this.captionsMime_ = '';
+  /** @private {!Array.<string>} */
+  this.captionsMime_ = [];
 };
 goog.inherits(shaka.player.DashVideoSource, shaka.player.StreamVideoSource);
 
@@ -94,21 +94,21 @@ shaka.player.DashVideoSource.ContentProtectionCallback;
 
 
 /**
- * Uses the given URL as a source for text tracks in addition to those
+ * Adds the given URL as a source for text tracks in addition to those
  * specified in the MPD.  This has no effect after load().
  *
  * @param {string} url The |url| of the file to load from.
- * @param {string=} opt_lang Optional language of the text tracks,
+ * @param {string=} opt_lang Optional language of the text track,
  *         defaults to 'en'.
  * @param {string=} opt_mime Optional MIME type of the file, defaults
  *          to 'text/vtt'.
  * @export
  */
 shaka.player.DashVideoSource.prototype.addExternalCaptions =
     function(url, opt_lang, opt_mime) {
-  this.captionsUrl_ = url;
-  this.captionsLang_ = opt_lang || '';
-  this.captionsMime_ = opt_mime || '';
+  this.captionsUrl_.push(url);
+  this.captionsLang_.push(opt_lang || '');
+  this.captionsMime_.push(opt_mime || '');
 };
 
 
@@ -125,9 +125,9 @@ shaka.player.DashVideoSource.prototype.load = function(preferredLanguage) {
   return mpdRequest.send().then(shaka.util.TypedBind(this,
       /** @param {!shaka.dash.mpd.Mpd} mpd */
       function(mpd) {
-        if (!!this.captionsUrl_) {
-          mpd.addExternalCaptions(this.captionsUrl_,
-                                  this.captionsLang_, this.captionsMime_);
+        for (var i = 0; i < this.captionsUrl_.length; i++) {
+          mpd.addExternalCaptions(this.captionsUrl_[i],
+                                  this.captionsLang_[i], this.captionsMime_[i]);
         }
 
         var mpdProcessor =

spec/mpd_spec.js

@@ -592,4 +592,35 @@ describe('mpd', function() {
     var representation = adaptationSet.representations[0];
     expect(representation.baseUrl.toString()).toBe('http://example.com/');
   });
+
+  it('handles adding multiple external captions', function() {
+    var source = [
+      '<MPD>',
+      '  <Period id="1" duration="PT0H1M0.00S">',
+      '  </Period>',
+      '</MPD>'].join('\n');
+
+    var mpd = shaka.dash.mpd.parseMpd(source, '');
+    mpd.addExternalCaptions('http://example.com/');
+    mpd.addExternalCaptions('http://example.com/', 'es');
+
+    var period = mpd.periods[0];
+    expect(period.adaptationSets.length).toBe(2);
+
+    var adaptationSet = period.adaptationSets[0];
+    expect(adaptationSet.contentType).toBe('text');
+    expect(adaptationSet.lang).toBe('en');
+    expect(adaptationSet.representations.length).toBe(1);
+
+    var representation = adaptationSet.representations[0];
+    expect(representation.baseUrl.toString()).toBe('http://example.com/');
+
+    var adaptationSet2 = period.adaptationSets[1];
+    expect(adaptationSet2.contentType).toBe('text');
+    expect(adaptationSet2.lang).toBe('es');
+    expect(adaptationSet2.representations.length).toBe(1);
+
+    var representation2 = adaptationSet2.representations[0];
+    expect(representation.baseUrl.toString()).toBe('http://example.com/');
+  });
 });

spec/player_integration.js

@@ -438,6 +438,21 @@ describe('Player', function() {
         done();
       });
     });
+
+    it('can be called multiple times', function(done) {
+      var source = newSource(plainManifest);
+      source.addExternalCaptions(captionFile);
+      source.addExternalCaptions(captionFile, 'es');
+
+      player.load(source).then(function() {
+        var tracks = player.getTextTracks();
+        expect(tracks.length).toBe(2);
+        done();
+      }).catch(function(error) {
+        fail(error);
+        done();
+      });
+    });
   });
 
   describe('enableTextTrack', function() {