Fix shortcut creation via Create Application Shortcuts... command.
Fix shortcut creation via Create Application Shortcuts... command.

Some changes related to the new bookmarks app flow, which always creates
an extension, assumed there would always be an extension. This isn't
true for the old application shortcuts (which are currently enabled by
default).

BUG=449412

Review URL: https://codereview.chromium.org/853563006

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#312164}

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