Update Edge workaround in DrmEngine.

Edge recently pushed an update which fixed a bug that we were working
around.  This was that it didn't support multiple MIME types when
querying EME.  Now it will allow multiples to be passed in.

However, Edge's update also introduced a new bug that when getting the
configuration from the access object, it doesn't report the correct
MIME types.  It should include every MIME type that is supported,
but it only includes the first one.

Closes #634

Change-Id: I7156887a112dc844b3cbc9bb2dd9676afee6cf56

lib/media/drm_engine.js

@@ -383,9 +383,6 @@ shaka.media.DrmEngine.prototype.prepareMediaKeyConfigs_ =
     function(manifest, offline, configsByKeySystem, keySystemsInOrder) {
   var clearKeyDrmInfo = this.configureClearKey_();
 
-  // TODO: Remove once Edge has released a fix for https://goo.gl/vr2Vle
-  var isEdge = navigator.userAgent.indexOf('Edge/') >= 0;
-
   manifest.periods.forEach(function(period) {
     period.streamSets.forEach(function(streamSet) {
       if (streamSet.type == 'text')
@@ -444,14 +441,6 @@ shaka.media.DrmEngine.prototype.prepareMediaKeyConfigs_ =
             drmInfo.keyIds.push(stream.keyId);
           }
 
-          // Edge 13 fails this negotiation with NotSupportedError if more than
-          // one entry is given, even if each entry individually would be
-          // supported.  Bug filed: https://goo.gl/vr2Vle
-          // TODO: Remove once Edge has released a fix.
-          if (isEdge && drmInfo.keySystem == 'com.microsoft.playready' &&
-              capabilities.length) {
-            return;
-          }
           capabilities.push({
             robustness: robustness,
             contentType: fullMimeType
@@ -524,19 +513,25 @@ shaka.media.DrmEngine.prototype.queryMediaKeys_ =
   p = p.then(function(mediaKeySystemAccess) {
     if (this.destroyed_) return Promise.reject();
 
+    // TODO: Remove once Edge has released a fix for https://goo.gl/qMeV7v
+    var isEdge = navigator.userAgent.indexOf('Edge/') >= 0;
+
     // Store the capabilities of the key system.
     var realConfig = mediaKeySystemAccess.getConfiguration();
     var audioCaps = realConfig.audioCapabilities || [];
     var videoCaps = realConfig.videoCapabilities || [];
     var caps = audioCaps.concat(videoCaps);
     this.supportedTypes_ = caps.map(function(c) { return c.contentType; });
-    if (this.supportedTypes_.length == 0) {
-      // Edge 13 does not report capabilities.  To work around this, set the
-      // supported types to null, which Player will use as a signal that the
-      // information is not available.
-      // See: https://goo.gl/0cSuT2
+    if (isEdge) {
+      // Edge 14 does not report correct capabilities.  It will only report the
+      // first MIME type even if the others are supported.  To work around this,
+      // set the supported types to null, which Player will use as a signal that
+      // the information is not available.
+      // See: https://goo.gl/qMeV7v
       this.supportedTypes_ = null;
     }
+    goog.asserts.assert(!this.supportedTypes_ || this.supportedTypes_.length,
+                        'We should get at least one supported MIME type');
 
     var originalConfig = configsByKeySystem[mediaKeySystemAccess.keySystem];
     this.createCurrentDrmInfo_(