Initial support for accessible text fields and focus tracking in ARC++

chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js

Index: chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js
diff --git a/chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js b/chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js
index 480b444c698145795f5bd4540066957649fa0563..b19fb53548fa3932d691b4df9002be96e59215cc 100644
--- a/chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js
+++ b/chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js
@@ -142,7 +142,7 @@ cursors.Cursor.prototype = {
     for (var i = 0; i < this.ancestry_.length; i++) {
       var firstValidNode = this.ancestry_[i];
       if (firstValidNode != null && firstValidNode.role !== undefined &&
-          firstValidNode.root !== undefined) {
+          firstValidNode.root != undefined) {

[hidehiko, 2017/03/21 03:43:23]

nit: looks unnecessary change? (Or any reasons to relax the condition...?)

[David Tseng, 2017/03/21 16:41:16]

It actually is. There are some cases, particularly in text fields, where the
text field node is detached and its parent is set to null (not undefined).

[hidehiko, 2017/03/21 22:00:43]

firstValidNode.root can be null, I think it's nice to comment (or explicitly
check either null or undefined), for future maintenance.

         return firstValidNode;
       }
       // If we have to walk up to an ancestor, reset the index to NODE_INDEX.
@@ -176,9 +176,9 @@ cursors.Cursor.prototype = {
     // Selections over line break nodes are broken.
     var parent = adjustedNode.parent;
     var grandparent = parent && parent.parent;
-    if (parent.role == RoleType.LINE_BREAK) {
+    if (parent && parent.role == RoleType.LINE_BREAK) {
       adjustedNode = grandparent;
-    } else if (grandparent.role == RoleType.LINE_BREAK) {
+    } else if (grandparent && grandparent.role == RoleType.LINE_BREAK) {
       adjustedNode = grandparent.parent;
     } else if (this.index_ == cursors.NODE_INDEX ||
         adjustedNode.role == RoleType.INLINE_TEXT_BOX ||