Show icon indicating extension in Extension Manager is available for update

[AllThingsSmitty]

If you open Extension Manager in Brackets the "Installed" icon will indicate if an update is available for extensions. It would be good to see the same call-to-action icon (green circle) used on Extension Manager icon (below the Live Preview icon) so a user knows one is available there.

[lkcampbell]

+1 on this. Good idea.

[lkcampbell]

If @larz0 can make an icon for this, I would be glad to do the pull request for this addition.

[peterflynn]

Yep, definitely. We've talked about this a bunch but I don't think there's any bug or backlog item tracking it yet (other than the "full" extension updates story).

We can presumably reuse the green-circle overlay from the Extension Manager dialog, so I'm not sure we need any additional icons.

I think we've talked about doing a once per 24-hrs ping to check for updates, similar to how we check for Brackets updates. We should probably double check with @jrowny about the bandwidth implications of this though, since his company is hosting the extension registry.

[lkcampbell]

@peterflynn, sounds good. Do you want me to talk to @jrowny, or do you guys want to do it and let me know what the next steps are?

[larz0]

@lkcampbell I won't have laptop access til Feb 6 but here's a comp from an old discussion:

https://f.cloud.github.com/assets/1495261/1467328/8b0bf01e-4580-11e3-8700-b94a6805eba9.png

It's relatively smaller than the update count on the tab so that people won't notice it while they're focusing on work.

[peterflynn]

@larz0 Man, that's really subtle! Maybe if it's not too much trouble @lkcampbell could try out a couple slightly larger radii for the dot (once a PR is up) and post screenshots to see how they compare?

[larz0]

@peterflynn sounds good because I actually don't feel strongly about it. Here's the old discussion thread:

#5838

[ingorichter]

Why can't we change the color of the icon in a subtle way? Make the icon glow and add a halo to it.

[larz0]

I actually don't mind the entire icon being green when there are updates.

[dangoor]

Hey @lkcampbell. I'll get in touch with @jrowny, but I'm guessing that an update ping every 24 hours will be fine. We were planning to do that all along anyhow. So, I think it's fine to get started on this.

[lkcampbell]

@dangoor, sounds good, I will start working on the PR.

[peterflynn]

Yay!

[AllThingsSmitty]

Fantastic!

[lkcampbell]

Okay, I finally had some time to make progress on this but there are still a few design issues I would like feedback on before I commit the PR.

The icon turns green when updates are available. The green is the same color as the green circle background in the update count in the Extension Manager.

The code checks the extension registry every 24 hours, assuming the icon has not already been turned green. If there are one or more updates available for installed extensions, the icon is turned green.

This icon stays green until the Extension Manager is opened (via the icon or the menu entry or whatever). The moment the Extension Manager is opened, the icon changes back to light gray; its job is done at this point.

Whatever the user decides to do once the Extension Manager is opened does not affect the icon in any way. For example, if the user opens the Extension Manager, looks at the updates available, and decides to update some, all, or none of the extensions, the icon will still remain light gray in all cases.

After 24 hours, the cycle restarts.

Let me know if you have any concerns or suggestions. Otherwise, this is the design of the PR I am committing in the next day or two.