Support additional sources for the theme color

[freaktechnik]

Vivaldi Fox currently only uses the theme-color meta tag. However some sites only specify the color in their web app manifest (as theme_color, or sometimes background_color may apply too).

Other potential sources include the status bar being set to black for iOS apps or the windows tile color.

I made a quick proof-of-concept to see what those sources would look like at https://github.com/freaktechnik/website-color/blob/master/content.js

I don't think the windows tile color is a good fit, since most websites that define it don't use a color matching their page, but one complementing their icon (see for example imgur).

[nt1m]

@freaktechnik Great idea! Thanks for finding all these sources! I used to support msApplication-tile in the SDK version, but it didn't give nice results as you said.

Would you like to make a PR ? All the magic happens in these files:

https://github.com/nt1m/vivaldi-fox/blob/master/background/color-utils.js#L103
https://github.com/nt1m/vivaldi-fox/blob/master/data/contentscript.js

[nt1m]

I've added this in the latest beta version: https://github.com/nt1m/vivaldi-fox/releases/tag/v3.0b1