Revert use of new Function() in player config.

Chrome App Content Security Policy prohibits use of new Fuction()
method. Revert the change that introduced it.

Closes #487

Change-Id: Id38522318affb9c5be8f6d2f4446e2967b43f58b

lib/offline/storage.js

@@ -498,7 +498,14 @@ shaka.offline.Storage.prototype.defaultTrackSelect_ = function(tracks) {
 shaka.offline.Storage.prototype.defaultConfig_ = function() {
   return {
     trackSelectionCallback: this.defaultTrackSelect_.bind(this),
-    progressCallback: new Function('storedContent', 'percent', '')
+    progressCallback: function(storedContent, percent) {
+      // Reference arguments to keep closure from removing it.
+      // If the argument is removed, it breaks our function length check
+      // in mergeConfigObjects_().
+      // NOTE: Chrome App Content Security Policy prohibits usage of new
+      // Function().
+      if (storedContent || percent) return null;
+    }
   };
 };
 

lib/player.js

@@ -1191,7 +1191,16 @@ shaka.Player.prototype.defaultConfig_ = function() {
     manifest: {
       retryParameters: shaka.net.NetworkingEngine.defaultRetryParameters(),
       dash: {
-        customScheme: new Function('node', ''),
+        customScheme: function(node) {
+          // Reference node to keep closure from removing it.
+          // If the argument is removed, it breaks our function length check
+          // in mergeConfigObjects_().
+          // TODO: Find a better solution if possible.
+          // NOTE: Chrome App Content Security Policy prohibits usage of new
+          // Function()
+
+          if (node) return null;
+        },
         clockSyncUri: ''
       }
     },