Manage seekable ranges for live streams

Use the experimental implementation of MediaSource.addSeekableRange_() to allow HLS to specify greater seekable ranges then the current buffered region. Requires https://github.com/videojs/videojs-contrib-media-sources/pull/55.

@@ -493,25 +493,26 @@ videojs.HlsHandler.prototype.updateDuration = function(playlist) {
       setDuration = function() {
         this.mediaSource.duration = newDuration;
         this.tech_.trigger('durationchange');
+
+        // update seekable
+        if (seekable.length !== 0 && newDuration === Infinity) {
+          this.mediaSource.addSeekableRange_(seekable.start(0), seekable.end(0));
+        }
         this.mediaSource.removeEventListener('sourceopen', setDuration);
       }.bind(this),
       seekable = this.seekable();
 
-  // TODO: Move to videojs-contrib-media-sources
-  if (seekable.length && newDuration === Infinity) {
-    if (isNaN(oldDuration)) {
-      oldDuration = 0;
-    }
-    newDuration = Math.max(oldDuration,
-      seekable.end(0) + playlist.targetDuration * 3);
-  }
-
   // if the duration has changed, invalidate the cached value
   if (oldDuration !== newDuration) {
+    // update the duration
     if (this.mediaSource.readyState !== 'open') {
       this.mediaSource.addEventListener('sourceopen', setDuration);
     } else if (!this.sourceBuffer || !this.sourceBuffer.updating) {
       this.mediaSource.duration = newDuration;
+      // update seekable
+      if (seekable.length !== 0 && newDuration === Infinity) {
+        this.mediaSource.addSeekableRange_(seekable.start(0), seekable.end(0));
+      }
       this.tech_.trigger('durationchange');
     }
   }

@@ -134,11 +134,6 @@ var
       type: 'sourceopen',
       swfId: player.tech_.el().id
     });
-
-    // endOfStream triggers an exception if flash isn't available
-    player.tech_.hls.mediaSource.endOfStream = function(error) {
-      this.error_ = error;
-    };
   },
   standardXHRResponse = function(request) {
     if (!request.url) {
@@ -170,6 +165,11 @@ var
   // a no-op MediaSource implementation to allow synchronous testing
   MockMediaSource = videojs.extend(videojs.EventTarget, {
     constructor: function() {},
+    duration: NaN,
+    seekable: videojs.createTimeRange(),
+    addSeekableRange_: function(start, end) {
+      this.seekable = videojs.createTimeRange(start, end);
+    },
     addSourceBuffer: function() {
       return new (videojs.extend(videojs.EventTarget, {
         constructor: function() {},
@@ -179,7 +179,10 @@ var
         remove: function() {}
       }))();
     },
-    endOfStream: function() {}
+    // endOfStream triggers an exception if flash isn't available
+    endOfStream: function(error) {
+      this.error_ = error;
+    }
   }),
 
   // do a shallow copy of the properties of source onto the target object
@@ -1385,7 +1388,7 @@ test('seeking in an empty playlist is a non-erroring noop', function() {
   equal(requests.length, requestsLength, 'made no additional requests');
 });
 
-test('tech\'s duration reports Infinity for live playlists', function() {
+test('sets seekable and duration for live playlists', function() {
   player.src({
     src: 'http://example.com/manifest/missingEndlist.m3u8',
     type: 'application/vnd.apple.mpegurl'
@@ -1394,13 +1397,19 @@ test('tech\'s duration reports Infinity for live playlists', function() {
 
   standardXHRResponse(requests[0]);
 
-  strictEqual(player.tech_.duration(),
-              Infinity,
-              'duration on the tech is infinity');
+  equal(player.tech_.hls.mediaSource.seekable.length,
+        1,
+        'set one seekable range');
+  equal(player.tech_.hls.mediaSource.seekable.start(0),
+        player.tech_.hls.seekable().start(0),
+        'set seekable start');
+  equal(player.tech_.hls.mediaSource.seekable.end(0),
+        player.tech_.hls.seekable().end(0),
+        'set seekable end');
 
-  notEqual(player.tech_.hls.mediaSource.duration,
+  strictEqual(player.tech_.hls.mediaSource.duration,
               Infinity,
-              'duration on the mediaSource is not infinity');
+              'duration on the mediaSource is infinity');
 });
 
 test('live playlist starts three target durations before live', function() {