Improved isInteresting heuristic, made more AutomationNodes focusable

chrome/browser/resources/chromeos/switch_access/tree_walker.js

Index: chrome/browser/resources/chromeos/switch_access/tree_walker.js
diff --git a/chrome/browser/resources/chromeos/switch_access/tree_walker.js b/chrome/browser/resources/chromeos/switch_access/tree_walker.js
index ce8237d798caa62c4a6254fa95f20a4b5366199a..5fc9f1f1d44316a6d0beab9c56a4c1b501bc89fe 100644
--- a/chrome/browser/resources/chromeos/switch_access/tree_walker.js
+++ b/chrome/browser/resources/chromeos/switch_access/tree_walker.js
@@ -116,11 +116,32 @@ AutomationTreeWalker.prototype = {
    * Returns true if |node| is interesting.
    *
    * @param {!chrome.automation.AutomationNode} node
-   * @return {boolean|undefined}
+   * @return {boolean}
    * @private
    */
   isInteresting_: function(node) {
-    return node.state && node.state.focusable;
+    let loc = node.location;
+    let parent = node.parent;
+    let root = node.root;
+    let role = node.role;
+    let state = node.state;
+
+    // Skip things that are offscreen
+    if (state[chrome.automation.StateType.OFFSCREEN]
+        || loc.top < 0 || loc.left < 0)
+      return false;
+
+    if (parent) {
+      // crbug.com/710559
+      // Work around for browser tabs
+      if (role === chrome.automation.RoleType.TAB
+          && parent.role === chrome.automation.RoleType.TAB_LIST
+          && root.role === chrome.automation.RoleType.DESKTOP)
+        return true;
+    }
+
+    // The general rule that applies to everything.
+    return state[chrome.automation.StateType.FOCUSABLE] === true;
   },
 
   /**