Remove irrelevant TODO

GetLayoutObject() is a getter on the AXObject, and will be null in the
case of display locking, because any AXObject inside display locking
will always be an AXNodeObject and return nullptr for GetLayoutObject().
There is no concern about dangling pointers as there theoretically can
be with node->GetLayoutObject().

TBR=aboxhall@chromium.org
NOTRY=true

Bug: None
Change-Id: I3319b1cd3f71d8af345d75dea868a7f0c23487bd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2575829Reviewed-by: Aaron Leventhal <aleventhal@chromium.org>
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#834227}

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

@@ -476,8 +476,6 @@ bool AXNodeObject::ComputeAccessibilityIsIgnored(
   if (role_ == ax::mojom::blink::Role::kRootWebArea)
     return false;
 
-  // TODO(accessibility) In the case of display locking, might we have a stale
-  // pointer to a layout object? Should the display locking case be first?
   if (GetLayoutObject()) {
     if (role_ == ax::mojom::blink::Role::kUnknown) {
       if (ignored_reasons)