Windows file associations: Search for shim in Chrome version directory.
Windows file associations: Search for shim in Chrome version directory.

Previously, would search for app_shim.exe in the Chrome application
directory, for example:

C:\Program Files\Google\Chrome\Application

Now searches in the Chrome version directory, for example:

C:\Program Files\Google\Chrome\Application\42.0.2277.0

which is where all version-specific files should be stored.

Note: The installer does not currently place app_shim.exe anywhere, so
we do not need to update its location. Users who have manually copied
app_shim.exe into the application directory will need to move it into
the version directory after this change.

Also gives a better error message if app_shim.exe is not found.

BUG=430760

Review URL: https://codereview.chromium.org/838793004

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#311800}

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