Cleanup and remove dead code in SetFocusedElement

This early-out was added in:

https://crrev.com/ce8ea3446283965c7eabab592cbffe223b1cf2bc

Back then, we applied fragment focus in LayoutUpdated() which could
cause this issue. This got cleaned up in:

https://crrev.com/45236fd563e9df53dc45579be1f3d0b4784885a2

so that focus is no longer applied after layout.

+Cleanup: Goto considered harmful

Bug: 795381
Change-Id: Ifeb4d2e03e872fd48cca6720b1d4de36ad1ecbb7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1524417
Commit-Queue: David Bokan <bokan@chromium.org>
Reviewed-by: Stefan Zager <szager@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641101}
static void AssertLayoutTreeUpdated(Node& root) {
  Node* node = &root;
  while (node) {
    if (RuntimeEnabledFeatures::DisplayLockingEnabled() &&
        node->IsElementNode() &&
        ToElement(node)->StyleRecalcBlockedByDisplayLock()) {
      node = FlatTreeTraversal::NextSkippingChildren(*node);
      continue;
    }

    DCHECK(!node->NeedsStyleRecalc());
    DCHECK(!node->ChildNeedsStyleRecalc());
    DCHECK(!node->NeedsReattachLayoutTree());
    DCHECK(!node->ChildNeedsReattachLayoutTree());
    DCHECK(!node->ChildNeedsDistributionRecalc());
    DCHECK(!node->NeedsStyleInvalidation());
    DCHECK(!node->ChildNeedsStyleInvalidation());
    DCHECK(!node->GetForceReattachLayoutTree());
    DCHECK((node->IsDocumentNode() || !node->GetLayoutObject() ||
            FlatTreeTraversal::Parent(*node)))
        << *node;

    node = FlatTreeTraversal::Next(*node);
  }
}

static void AssertLayoutTreeUpdated(Node& root) {
  Node* node = &root;
  while (node) {
    if (RuntimeEnabledFeatures::DisplayLockingEnabled() &&
        node->IsElementNode() &&
        ToElement(node)->StyleRecalcBlockedByDisplayLock()) {
      node = FlatTreeTraversal::NextSkippingChildren(*node);
      continue;
    }

    DCHECK(!node->NeedsStyleRecalc());
    DCHECK(!node->ChildNeedsStyleRecalc());
    DCHECK(!node->NeedsReattachLayoutTree());
    DCHECK(!node->ChildNeedsReattachLayoutTree());
    DCHECK(!node->ChildNeedsDistributionRecalc());
    DCHECK(!node->NeedsStyleInvalidation());
    DCHECK(!node->ChildNeedsStyleInvalidation());
    DCHECK(!node->GetForceReattachLayoutTree());
    DCHECK((node->IsDocumentNode() || !node->GetLayoutObject() ||
            FlatTreeTraversal::Parent(*node)))
        << *node;

    node = FlatTreeTraversal::Next(*node);
  }
}
