The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/085b7a32b1c1c2a60ed5ed39945d7053f83a5472

commit 085b7a32b1c1c2a60ed5ed39945d7053f83a5472
Author: Aaron Leventhal <aleventhal@chromium.org>
Date: Wed Nov 14 19:07:35 2018

Use MarkAXObjectDirty()

This updates the code to use MarkAXObjectDirty() where we were using a
hack to fire value changes for generic tree changes. However, tree
change serialization/deserialization did not handle bundles where
there were only changed objects, and no events were provided.

Bug:  902324 
Change-Id: I93f6a1ae1f2e7d835621af8f8deb6c62043454fe
Reviewed-on: https://chromium-review.googlesource.com/c/1318361
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608072}
[modify] https://crrev.com/085b7a32b1c1c2a60ed5ed39945d7053f83a5472/content/browser/frame_host/render_frame_host_impl.cc
[modify] https://crrev.com/085b7a32b1c1c2a60ed5ed39945d7053f83a5472/content/renderer/accessibility/render_accessibility_impl.cc
[modify] https://crrev.com/085b7a32b1c1c2a60ed5ed39945d7053f83a5472/third_party/blink/renderer/modules/accessibility/ax_layout_object.cc
[modify] https://crrev.com/085b7a32b1c1c2a60ed5ed39945d7053f83a5472/third_party/blink/renderer/modules/accessibility/ax_object_cache_impl.cc