Chrome for Android allows devs to theme the UI with the meta-tag "metatheme". That sets the primary color and Chrome then automatically calculates a darker shade for the statusbar (primary dark color). See attached image for an example.
Now, Material Design generally says you should use a "500" color as a primary and a "700"-shade of that same color as the primary dark color. But since Chrome automatically calculates this value (and the 500/700 difference depends on the color) it doesn't completely match the Material colors and is difficult to predict without the formula Chrome uses.
So my question is: what formula does Chrome use to calculate the darker shade so I can predict it?
Related post: Meta themecolor in Chrome