GitLab

Added functionality for AXNode::PosInSet(), which determines a node's
position within an ordered container, and AXNode::SetSize, which
determines the total number of elements within the node's container.

Change-Id: Idd1849891db8cb96c30edda4d4b85b9a206220f2
Reviewed-on: https://chromium-review.googlesource.com/c/1336327
Commit-Queue: Akihiro Ota <akihiroota@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608241}