mat-slider-toggle not using correct color. (ignoring hue)

[robindijkhof]

Bug, feature request, or proposal:

Bug

What is the expected behavior?

mat-slider-toggle should use the exact same color as the primary color.

What is the current behavior?

It is ignoring the hue/tint (not sure what it is called)

What are the steps to reproduce?

Providing a StackBlitz reproduction is the best way to share your issue.

https://github.com/robindijkhof/mat-slide-toggle

While my primary color is: $app-primary: mat-palette($mat-blue, 900);. it is ignoring the 900

What is the use-case or motivation for changing an existing behavior?

Incorrect behaviour

Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Angular 6.0.3
Material 6.3.0

Is there anything else we should know?

[devversion]

Previously, with the old Material Design guidelines, the hue colors were explicitly defined (e.g. see #1568)

checked = Hue 500 (light);
checked = Hue 200 (dark)

I'm not sure whether it makes sense to use the default hue that can be customized by the user here.

The slide-toggle won't always look good in dark themes by default, meaning that the user needs to customize his palette and adjust the default hue.

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However I see that there needs to be a way to match those colors. One possibility would be to default to the current logic if the default hue is not changed to a different value (e.g. from 500 to 900)

[robindijkhof]

@devversion In my opinion it make sense to use the default hue. That's because it it a formcontrol and all other formcontrols AFAIK do use the hue.

[devversion]

I've mentioned the issue in the team meeting and since it would be a visually breaking change we don't want to switch to the default hue yet.

The new design specifications are not very explicit about the proper hue, but the old version was. I will continue researching about the proper hue. Just making clear that this will be a low priority.