No longer ask AccessibilityIsIgnored to compute Ignored reasons

The ignored reasons were not being used, so no need to ask.

Bug: 972643
Change-Id: Iccb3fa6b4760094719a51b0131e1a1f0514f4b75
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1659598Reviewed-by: Kevin Babbitt <kbabbitt@microsoft.com>
Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Commit-Queue: Jacques Newman <janewman@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#669899}

third_party/blink/renderer/modules/accessibility/ax_object.cc

@@ -909,8 +909,7 @@ void AXObject::UpdateCachedAttributeValuesIfNeeded() const {
   cached_is_descendant_of_disabled_node_ = !!DisabledAncestor();
   cached_has_inherited_presentational_role_ =
       !!InheritsPresentationalRoleFrom();
-  IgnoredReasons ignored_reasons;
-  cached_is_ignored_ = ComputeAccessibilityIsIgnored(&ignored_reasons);
+  cached_is_ignored_ = ComputeAccessibilityIsIgnored();
   cached_is_editable_root_ = ComputeIsEditableRoot();
   // Compute live region root, which can be from any ARIA live value, including
   // "off", or from an automatic ARIA live value, e.g. from role="status".