Bug 1298436 - Don't get caught in an endless loop when narrating last...

Bug 1298436 - Don't get caught in an endless loop when narrating last paragraph. r=jaws, a=lizzard CLOSED TREE

This version does not have the breaking test.

MozReview-Commit-ID: 7OZctto5QBF

--HG--
extra : source : aaca2a928eda6417bef2fde8ad5fa5a45c5fc3af

toolkit/components/narrate/Narrator.jsm

@@ -144,8 +144,8 @@ Narrator.prototype = {
     this._win.speechSynthesis.cancel();
     let tw = this._treeWalker;
     let paragraph = tw.currentNode;
-    if (!paragraph) {
-      tw.currentNode = tw.root;
+    if (paragraph == tw.root) {
+      this._sendTestEvent("paragraphsdone", {});
       return Promise.resolve();
     }
 
@@ -193,7 +193,7 @@ Narrator.prototype = {
           // User pressed stopped.
           resolve();
         } else {
-          tw.nextNode();
+          tw.currentNode = tw.nextNode() || tw.root;
           this._speakInner().then(resolve, reject);
         }
       });