some plugins are not loaded in time

[elaihau]

Description

Task providers are not registered on Theia startup. Take npm for example, the npm tasks are not loaded until package.json is opened.

Reproduction Steps

See GIF

OS and Theia version:
Ubuntu 18.04. Chrome. Theia example-browser, master branch as of Aug 5 2019.

Diagnostics:
Looks like "loading some plugins" is now event-driven?
Talked with @vince-fugnitto. We think probably it is related to this commit 6021d79 @akosyakov

[akosyakov]

Metadata should be loaded in advance, activation events only to run the extension code. Is it something what is contributed by code?

[akosyakov]

There is though one activation event which is not covered yet: https://github.com/microsoft/vscode/blob/051b669b61cd175cb06c8f4500498dbeef79114c/extensions/npm/package.json#L32

We should study maybe it should be activated before running any task.

[akosyakov]

@elaihau i will try to address it with a new activation event.