The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/de17d566c402e75179dd38750885d4e7f329124f

commit de17d566c402e75179dd38750885d4e7f329124f
Author: Dominic Mazzoni <dmazzoni@chromium.org>
Date: Mon Nov 06 23:15:45 2017

Check return value from SerializeChanges in SnapshotAccessibilityTree

When generating a snapshot of the accessibility tree (for Google Assistant
or Now On Tap on Android) occasionally the serialization fails the first
time. We were ignoring the return value, leading to a crash later.

On one particular url (https://m.youtube.com/watch?v=3P6DWAwwViU&app=m)
I determined that serialization failed due to aria-owns rearranging the
tree. It succeeds the second time.

I tried for several hours to turn that page into a minimal repro, with
no luck. The bug disappears if I try to change the page, it seems
very sensitive to the exact details.

I think it's important to land this fix even without a
regression test.

Bug:  781058 ,765490
Change-Id: Iccd3b4e1b9f178b2c3be6da8784a656dbb0c904a
Reviewed-on: https://chromium-review.googlesource.com/752573
Reviewed-by: Aaron Leventhal <aleventhal@chromium.org>
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#514281}
[modify] https://crrev.com/de17d566c402e75179dd38750885d4e7f329124f/content/renderer/accessibility/render_accessibility_impl.cc