Views style setup bar colors with a list form element

Problem/Motivation

When we make a new view with chart style , it don't allow customize bar colors. the color list is painful.

Proposed resolution

Maybe a setting field that allow add a comma separated list of web colors.
The best solution maybe a list of colors with a add buttom to add new colors.

Remaining tasks

Implement this.

User interface changes

Add a text field to add a comma separated list of colors or a color list in views style setting form.

API changes

N/A

Data model changes

N/A