commit 2469d759e3fe6a066300a7d4cc2ec24978692501
author Julie Jeongeun Kim <jkim@igalia.com> Wed Apr 08 11:18:34 2020
committer Commit Bot <commit-bot@chromium.org> Wed Apr 08 11:18:34 2020
tree 0ee24238ed1fd2022d182429bdb15c62cd81a6cc
parent 932a003431a965340a7eea96326a45e84fac61d9

a11y: AXPlatformNodeBase::GetIndexInParent() returns base::Optional

This fixes the regression issue from the CL[1] which moved
the logic of GetIndexInParent to AXPlatformNodeBase.

Before the CL[1], atk_object::GetIndexInParent returns -1 as an
invalid value but AXPlatformNodeBase::GetIndexInParent returns
positive numbers or 0 except the case when it's not implemented
or doesn't have |delegate_|. AXPlatformNodeBase::GetIndexInParent
is also used for the internal logic in AXPlatformNodeBase with
the assumption that the return value is not less than 0.
The CL[1] moved the logic to AXPlatformNodeBase::GetIndexInParent
with keeping the rule that the return value is not less than 0.

The problem is that screen reader such as Orca expects that it
returns -1 when it's invalid.

With this CL, AXPlatformNodeBase::GetIndexInParent() returns
base::Optional and the caller has -1 if GetIndexInParent() returns
base::nullopt. It also uses GetFirstChild and GetNextSibling for
children iteration in GetHypertextOffsetFromChild() and
GetHypertextOffsetFromEndpoint() instead of GetIndexInParent and
GetChildAt.

[1]https://crrev.com/c/2087234

Bug: 1065534
Change-Id: I00e2ed421ed263cf379ba22f55049fd52d32df9b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2129667
Commit-Queue: Julie Kim <jkim@igalia.com>
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Reviewed-by: Martin Robinson <mrobinson@igalia.com>
Reviewed-by: Joanmarie Diggs <jdiggs@igalia.com>
Cr-Commit-Position: refs/heads/master@{#757381}