Convert execCommand/outdent-nested-lists-*.html to use w3c test harness
This patch introduces "outdent_nested_lists.html" as a replacement of
"outdent-nested-lists-00[1-4].html" by utilizing w3c test harness with
|assert_selection()| assertion, since these tests are similar pattern, to
simplify test case 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
Committed:
https://crrev.com/1410c1cd2f9a526f1e89f7fc12c2e6131e8faf3f
Cr-Commit-Position: refs/heads/master@{#396768}