+dsexton just for his own reference

It seems ChromeVox is not able to navigate into webview anymore. This seems a regression. The most recent change is that we moved to use content service to create these webviews.

dmblack@ can you help verify if this regression is caused by content service integration?

Sure, looking into it...

I've confirmed that this regression was introduced when we migrated to using the content service.

Ken, I notice that the WebView code has logic to hande forwarding of focus to the underlying web contents:
https://cs.chromium.org/search/?q=focus+file:webview.cc&type=cs

Is there plans to do something similar for the views backing NavigableContentsView?

I did some rough investigation (which only considered the case of LocalViewHost) here:
https://chromium-review.googlesource.com/c/chromium/src/+/1359696

In general the plan for content service is to add features carefully, only as they're needed. This sounds like something we definitely need, though I admit my knowledge of this area (a11y and focus behavior in general) is pretty limited.

Is there any way to test the broken behavior without using assistant specifically? Like do any accessibility features break in a way that can be observed in a developer build?

Oh, nevermind. ChromeVox. Got it. I'll take a look, unless someone else understands this area better and can fix it faster. :)

Thanks for looking into it Ken! :)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/71e957aaa499195b5ccb380c66b6a734596cc49d

commit 71e957aaa499195b5ccb380c66b6a734596cc49d
Author: Ken Rockot <rockot@google.com>
Date: Mon Dec 10 20:49:53 2018

Fix assistant UI focus and ax behavior

This corrects the behavior of UI focus (including Tab cycling) and
accessibility interaction in the Chrome OS Assistant UI. This requires
minimal changes to Assistant code to forward focus events to its
NavigableContents.

More substantial changes are made to Content Service, namely:

- NavigableContents now supports forwarding simple focus events to its
  service-side WebContents impl
- NavigableContents now receives updates about AX tree changes from the
  service-side WebContents impl, and forwards them to the UI subsystem
  within the client process.

Bug:  910556 
Change-Id: Ic7010b966b0a7c5304861780462b6c82685b0184
Reviewed-on: https://chromium-review.googlesource.com/c/1366757
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Camille Lamy <clamy@chromium.org>
Commit-Queue: Ken Rockot <rockot@google.com>
Cr-Commit-Position: refs/heads/master@{#615244}
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/ash/assistant/ui/assistant_container_view.cc
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/ash/assistant/ui/assistant_container_view_focus_traversable.cc
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/ash/assistant/ui/assistant_web_view.cc
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/ash/assistant/ui/assistant_web_view.h
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/content/browser/content_service_delegate_impl.cc
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/navigable_contents_delegate.h
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/navigable_contents_impl.cc
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/navigable_contents_impl.h
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/public/cpp/BUILD.gn
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/public/cpp/DEPS
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/public/cpp/navigable_contents.cc
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/public/cpp/navigable_contents.h
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/public/cpp/navigable_contents_view.cc
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/public/cpp/navigable_contents_view.h
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/public/cpp/test/fake_navigable_contents.cc
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/public/cpp/test/fake_navigable_contents.h
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/public/mojom/BUILD.gn
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/public/mojom/navigable_contents.mojom
[modify] https://crrev.com/71e957aaa499195b5ccb380c66b6a734596cc49d/services/content/service_unittest.cc