Bug 1255261 - Read current paragraph after pressing stop. r=jaws

We always had to make sure we were one paragraph back from where we wanted
to start. That seems broken. I made it so that we start from the current
paragraph.

MozReview-Commit-ID: 4HMTdXcF644

toolkit/components/narrate/Narrator.jsm

@@ -143,7 +143,7 @@ Narrator.prototype = {
   _speakInner: function() {
     this._win.speechSynthesis.cancel();
     let tw = this._treeWalker;
-    let paragraph = tw.nextNode();
+    let paragraph = tw.currentNode;
     if (!paragraph) {
       tw.currentNode = tw.root;
       return Promise.resolve();
@@ -193,6 +193,7 @@ Narrator.prototype = {
           // User pressed stopped.
           resolve();
         } else {
+          tw.nextNode();
           this._speakInner().then(resolve, reject);
         }
       });
@@ -216,14 +217,10 @@ Narrator.prototype = {
       let tw = this._treeWalker;
       if (!this._isParagraphInView(tw.currentNode)) {
         tw.currentNode = tw.root;
-        while (tw.nextNode()) {
-          if (this._isParagraphInView(tw.currentNode)) {
-            break;
-          }
-        }
-        // _speakInner will advance to the next node for us, so we need
-        // to have it one paragraph back from the first visible one.
-        tw.previousNode();
+        while (tw.nextNode() && !this._isParagraphInView(tw.currentNode)) {}
+      }
+      if (tw.currentNode == tw.root) {
+        tw.nextNode();
       }
 
       return this._speakInner();

toolkit/components/narrate/test/browser_narrate.js

@@ -64,6 +64,19 @@ add_task(function* testNarrate() {
 
     NarrateTestUtils.isStartedState(content, ok);
 
+    paragraph = speechinfo.paragraph;
+    $(NarrateTestUtils.STOP).click();
+    yield ContentTaskUtils.waitForCondition(
+      () => !$(NarrateTestUtils.STOP), "transitioned to stopped state");
+    NarrateTestUtils.isStoppedState(content, ok);
+
+    promiseEvent = ContentTaskUtils.waitForEvent(content, "paragraphstart");
+    $(NarrateTestUtils.START).click();
+    speechinfo = (yield promiseEvent).detail;
+    is(speechinfo.paragraph, paragraph, "read same paragraph again");
+
+    NarrateTestUtils.isStartedState(content, ok);
+
     let eventUtils = NarrateTestUtils.getEventUtils(content);
 
     promiseEvent = ContentTaskUtils.waitForEvent(content, "paragraphstart");