[snap /from-source] broken launcher

[Ads20000]

Ran `snap install chromium --channel=candidate/from-source` as suggested in https://community.ubuntu.com/t/intent-to-provide-chromium-as-a-snap-only/5987 and I think it broke my launcher (from searching for Chromium in Activities).

Clicking on it produces the notification:

Failed to launch "Chromium Web Browser"
Desktop file didn't specify exec field

Also the launcher has no icon (only the plain executable one)

```
$ snap info chromium
tracking: candidate/from-source
refreshed: 2018-05-16T22:04:26+01:00
installed: 66.0.3359.181 (331) 238MB -
$ snap version
snap 2.32.8+18.04
snapd 2.32.8+18.04
series 16
ubuntu 18.04
kernel 4.15.0-20-generic
$ snap info core
tracking: beta
refreshed: 2018-05-11T15:51:12+01:00
installed: 16-2.32.8 (4650) 90MB core
```

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: chromium-browser (not installed)
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
Uname: Linux 4.15.0-20-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
CurrentDesktop: communitheme:ubuntu:GNOME
Date: Fri May 18 14:09:37 2018
InstallationDate: Installed on 2017-08-03 (287 days ago)
InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
SourcePackage: chromium-browser
UpgradeStatus: Upgraded to bionic on 2018-04-22 (26 days ago)

[Ads20000 (ads20000)]

Ran `snap refresh chromium --stable` and the launcher is fine, so this is a bug in /from-source alone.

[Olivier Tilloy (osomon)]

Thanks for the report Ads20000. I can confirm the issue, and am working on a fix.

[Olivier Tilloy (osomon)]

Tentative fix: https://git.launchpad.net/~chromium-team/chromium-browser/+git/snap-from-source/commit/?id=19d79ddbb8471b789b4e5ed920601c70ae4d26ba

A new snap is building and will be published in the candidate/from-source channel when ready.

[Ads20000 (ads20000)]

Launcher is fixed in Chromium 66.0.3359.181 (336) [candidate/from-source], thanks! :)