Convert undo-indent*.html to use w3c test harness
This patch changes "undo-indent.html" to use w3c test harness with
|assert_selection()| and merges "undo-indent-noneditable.html" into it
since both tests are similar pattern to simplify for source code for improving
code health.
This patch is a preparation of committing crrev.com/2001083002, Make
FrameSelection to track associated Document.
BUG=n/a
TEST=n/a; no behavior changes
Review-Url: https://codereview.chromium.org/2010333003
Cr-Commit-Position: refs/heads/master@{#396678}
4 files changed