Handle annotations with no resources.

src/annotation.js

@@ -142,6 +142,10 @@ var Annotation = (function AnnotationClosure() {
     loadResources: function(keys) {
       var promise = new Promise();
       this.appearance.dict.getAsync('Resources').then(function(resources) {
+        if (!resources) {
+          promise.resolve();
+          return;
+        }
         var objectLoader = new ObjectLoader(resources.map,
                                             keys,
                                             resources.xref);

test/test_manifest.json

@@ -1128,6 +1128,13 @@
       "rounds": 1,
       "type": "eq"
     },
+    {  "id": "bug886717",
+      "file": "pdfs/bug886717.pdf",
+      "md5": "8ba614192797a1324765610231a1bc9d",
+      "rounds": 1,
+      "type": "load",
+      "about": "Annotation that has no resources."
+    },
     {  "id": "issue3263",
       "file": "pdfs/issue3263.pdf",
       "md5": "cee1cf0bd7ce6681cdb97c8e42697d81",