GitLab

Move the helper functions for loading an accessibility dump expectation
file and validating a dump into their own test helper class. This is
purely code movement - no changes apart from fixing up dereferences
where necessary.

I originally wanted to add these methods to AccessibilityTreeFormatter
but that failed a presubmit check for LOG(INFO) spam.
AccessibilityTreeFormatter isn't test-only code - it's used from the
chrome://accessibility page - so I opted for creating a new class for
the test helper methods instead.

R=nektar@chromium.org

Bug: 974397
Change-Id: Ib9d5105747b1418c215c5d11020c92dedade099f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1669947
Commit-Queue: Kevin Babbitt <kbabbitt@microsoft.com>
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#671739}