Fix a failure in test_api.js when accessibility auditing is not enabled.
Fix a failure in test_api.js when accessibility auditing is not enabled.

Tests that don't enable auditing generate a confusing stack trace and
a setUp method that would call its base method by virtue of good practice
will not work.

BUG=458910

Review URL: https://codereview.chromium.org/927083003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#316570}

chuan9/chromium-crosswalk,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Just-D/chromium-1,Chilledheart/chromium,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Fireblend/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Just-D/chromium-1,hgl888/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Just-D/chromium-1,Fireblend/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Just-D/chromium-1,PeterWangIntel/chromium-crosswalk,Chilledheart/chromium,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,ltilve/chromium,Chilledheart/chromium,chuan9/chromium-crosswalk,chuan9/chromium-crosswalk,chuan9/chromium-crosswalk,Pluto-tv/chromium-crosswalk,fujunwei/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,ltilve/chromium,hgl888/chromium-crosswalk,Pluto-tv/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Fireblend/chromium-crosswalk,Fireblend/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,ltilve/chromium,fujunwei/chromium-crosswalk,ltilve/chromium,axinging/chromium-crosswalk,Chilledheart/chromium,TheTypoMaster/chromium-crosswalk,axinging/chromium-crosswalk,fujunwei/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,Fireblend/chromium-crosswalk,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,ltilve/chromium,hgl888/chromium-crosswalk,ltilve/chromium,chuan9/chromium-crosswalk,Chilledheart/chromium,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,hgl888/chromium-crosswalk,Fireblend/chromium-crosswalk,fujunwei/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,ltilve/chromium,Fireblend/chromium-crosswalk,chuan9/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,axinging/chromium-crosswalk,Chilledheart/chromium,fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,hgl888/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Just-D/chromium-1,Just-D/chromium-1,Just-D/chromium-1,chuan9/chromium-crosswalk,Pluto-tv/chromium-crosswalk,hgl888/chromium-crosswalk,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,ltilve/chromium,Fireblend/chromium-crosswalk,Chilledheart/chromium,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Pluto-tv/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Chilledheart/chromium,chuan9/chromium-crosswalk,hgl888/chromium-crosswalk,ltilve/chromium,Fireblend/chromium-crosswalk,fujunwei/chromium-crosswalk,TheTypoMaster/chromium-crosswalk