SwitchAccess ignore disabled elements

Refining the isActionable method to not include elements that are
disabled.

Bug: None
Change-Id: I05f85282904af5025615cf8efde6945f219bad20
Reviewed-on: https://chromium-review.googlesource.com/1206030Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Zach Helfinstein <zhelfins@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588988}

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

@@ -165,6 +165,10 @@ SwitchAccessPredicate.isActionable = function(node) {
   if (state[StateType.OFFSCREEN] || loc.top < 0 || loc.left < 0)
     return false;
 
+  // Skip things that are disabled.
+  if (node.restriction === chrome.automation.Restriction.DISABLED)
+    return false;
+
   // These web containers are not directly actionable.
   if (role === RoleType.WEB_VIEW || role === RoleType.ROOT_WEB_AREA)
     return false;