Fix bug w/ exception not being passed to error callbacks of a Promise

src/util.js

@@ -503,6 +503,7 @@ var Promise = PDFJS.Promise = (function PromiseClosure() {
     this.name = name;
     this.isRejected = false;
     this.error = null;
+    this.exception = null;
     // If you build a promise and pass in some data it's already resolved.
     if (data != null) {
       this.isResolved = true;
@@ -611,6 +612,7 @@ var Promise = PDFJS.Promise = (function PromiseClosure() {
 
       this.isRejected = true;
       this.error = reason || null;
+      this.exception = exception || null;
       var errbacks = this.errbacks;
 
       for (var i = 0, ii = errbacks.length; i < ii; i++) {
@@ -629,7 +631,8 @@ var Promise = PDFJS.Promise = (function PromiseClosure() {
         callback.call(null, data);
       } else if (this.isRejected && errback) {
         var error = this.error;
-        errback.call(null, error);
+        var exception = this.exception;
+        errback.call(null, error, exception);
       } else {
         this.callbacks.push(callback);
         if (errback)