Fix custom launcher pages showing when setEnabled(false) is called.
Fix custom launcher pages showing when setEnabled(false) is called.

This CL fixes an issue where the custom launcher page would still be
shown when the app list was opened even when setEnabled(false) was called.

BUG=462444

Review URL: https://codereview.chromium.org/958133005

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#318650}

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