This bug has an owner, thus, it's been triaged. Changing status to "assigned".

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/478dff1ed78138cb65eee0b013ff347f3d1ff8d4

commit 478dff1ed78138cb65eee0b013ff347f3d1ff8d4
Author: Randy Rossi <rmrossi@chromium.org>
Date: Thu Sep 27 20:02:11 2018

Remove duplicate ax tree code

This CL moves common logic between chrome & chromecast into a
common ui/views class.  Chrome/Chromecast specific logic differences
are handled in a delegate class.  Name/scope of this delegate may
change as we refactor move duplicate code out. Part of an on going
effort to eliminate duplicate code introduced when automation API
was added to Chromecast.

Test: Manual verification on chromecast (estelle) and chromeos (tidus)
Bug: 837773
Change-Id: Ia73513b09550d089daf09c89dd1fdda11bcacd4a
Reviewed-on: https://chromium-review.googlesource.com/1234363
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Reviewed-by: Alex Sakhartchouk <alexst@chromium.org>
Commit-Queue: Randy Rossi <rmrossi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594834}
[modify] https://crrev.com/478dff1ed78138cb65eee0b013ff347f3d1ff8d4/chrome/browser/ui/BUILD.gn
[modify] https://crrev.com/478dff1ed78138cb65eee0b013ff347f3d1ff8d4/chrome/browser/ui/aura/accessibility/automation_manager_aura.h
[modify] https://crrev.com/478dff1ed78138cb65eee0b013ff347f3d1ff8d4/chrome/browser/ui/aura/accessibility/ax_tree_source_aura.cc
[modify] https://crrev.com/478dff1ed78138cb65eee0b013ff347f3d1ff8d4/chrome/browser/ui/aura/accessibility/ax_tree_source_aura.h
[modify] https://crrev.com/478dff1ed78138cb65eee0b013ff347f3d1ff8d4/chromecast/browser/BUILD.gn
[modify] https://crrev.com/478dff1ed78138cb65eee0b013ff347f3d1ff8d4/chromecast/browser/ui/aura/accessibility/automation_manager_aura.h
[delete] https://crrev.com/2caacd58cfc0664b38be83169734dc5768e414b4/chromecast/browser/ui/aura/accessibility/ax_root_obj_wrapper.cc
[delete] https://crrev.com/2caacd58cfc0664b38be83169734dc5768e414b4/chromecast/browser/ui/aura/accessibility/ax_root_obj_wrapper.h
[modify] https://crrev.com/478dff1ed78138cb65eee0b013ff347f3d1ff8d4/chromecast/browser/ui/aura/accessibility/ax_tree_source_aura.cc
[modify] https://crrev.com/478dff1ed78138cb65eee0b013ff347f3d1ff8d4/chromecast/browser/ui/aura/accessibility/ax_tree_source_aura.h
[modify] https://crrev.com/478dff1ed78138cb65eee0b013ff347f3d1ff8d4/ui/views/BUILD.gn
[rename] https://crrev.com/478dff1ed78138cb65eee0b013ff347f3d1ff8d4/ui/views/accessibility/ax_root_obj_wrapper.cc
[rename] https://crrev.com/478dff1ed78138cb65eee0b013ff347f3d1ff8d4/ui/views/accessibility/ax_root_obj_wrapper.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f3d287f6e0d43a427c88dcfe3497352a4e46d6bf

commit f3d287f6e0d43a427c88dcfe3497352a4e46d6bf
Author: Randy Rossi <rmrossi@chromium.org>
Date: Mon Oct 01 19:45:15 2018

Remove more duplicate ax tree code

Part of ongoing effort to eliminate duplicate code
introduced when automation API was added to Chromecast.

Making Chromecast's copy of AXTreeSourceAura derive from
AXTreeSourceViews.  The two now nearly identical copies of
ax_tree_source_aura.cc will be merged and moved up to
ui/views in a subsequent CL.

Bug: 837773
Test: Manual verification on chromecast and chromeos (tidus)
Change-Id: I1b083280ce280ec0bd25324778f5d84ec3a7e9cf
Reviewed-on: https://chromium-review.googlesource.com/1249682
Commit-Queue: Randy Rossi <rmrossi@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Alex Sakhartchouk <alexst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595511}
[modify] https://crrev.com/f3d287f6e0d43a427c88dcfe3497352a4e46d6bf/chromecast/browser/ui/aura/accessibility/ax_tree_source_aura.cc
[modify] https://crrev.com/f3d287f6e0d43a427c88dcfe3497352a4e46d6bf/chromecast/browser/ui/aura/accessibility/ax_tree_source_aura.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a751644405461183211b0facdfee59a0fdda7bd8

commit a751644405461183211b0facdfee59a0fdda7bd8
Author: Randy Rossi <rmrossi@chromium.org>
Date: Thu Nov 22 16:50:45 2018

Move common accessibility IPC messages to extensions/common

These IPC extension messages are identical between chrome/chromecast.
Moving up to extensions/common

Bug: 837773
Test: Deploy ChromeOs manually (tidus)
Change-Id: I8884ea9726b69efb40c71614de11889bf01a2bb4
Reviewed-on: https://chromium-review.googlesource.com/c/1261976
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Randy Rossi <rmrossi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610442}
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chrome/browser/chromeos/arc/accessibility/ax_tree_source_arc.cc
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chrome/browser/extensions/api/automation_internal/automation_event_router.cc
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chrome/browser/extensions/api/automation_internal/automation_event_router.h
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chrome/browser/ui/apps/chrome_app_delegate.cc
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chrome/browser/ui/aura/accessibility/automation_manager_aura.cc
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chrome/browser/ui/aura/accessibility/automation_manager_aura_browsertest.cc
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chrome/common/extensions/chrome_extension_messages.h
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chrome/renderer/extensions/automation_ax_tree_wrapper.cc
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chrome/renderer/extensions/automation_internal_custom_bindings.cc
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chromecast/browser/extensions/api/automation_internal/automation_event_router.h
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chromecast/browser/ui/aura/accessibility/automation_manager_aura.cc
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chromecast/common/extensions_api/cast_extension_messages.h
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chromecast/renderer/extensions/automation_ax_tree_wrapper.cc
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/chromecast/renderer/extensions/automation_internal_custom_bindings.cc
[modify] https://crrev.com/a751644405461183211b0facdfee59a0fdda7bd8/extensions/common/extension_messages.h