[Switch Access] Detect menus and modal dialogs

If the user navigates to a modal or system menu (other than by focus
automatically jumping there), we should still use the custom behavior
for modals.

AX-Relnotes: n/a.
Bug: None.
Change-Id: Ie0b963f1540568cdd8f249ee016e787de45c0b3b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2270468
Auto-Submit: Anastasia Helfinstein <anastasi@google.com>
Reviewed-by: David Tseng <dtseng@chromium.org>
Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
Cr-Commit-Position: refs/heads/master@{#785946}

chrome/browser/resources/chromeos/accessibility/switch_access/nodes/node_wrapper.js

@@ -348,6 +348,11 @@ class RootNodeWrapper extends SARootNode {
          rootNode.parent.role === chrome.automation.RoleType.WINDOW)) {
       return WindowRootNode.buildTree(rootNode);
     }
+    if (rootNode.role === chrome.automation.RoleType.MENU ||
+        rootNode.role === chrome.automation.RoleType.MENU_BAR ||
+        rootNode.modal) {
+      return ModalDialogRootNode.buildTree(rootNode);
+    }
 
     const root = new RootNodeWrapper(rootNode);
     const childConstructor = (node) => NodeWrapper.create(node, root);