Summary:
RN offers checkbox component on android: https://facebook.github.io/react-native/docs/checkbox.html
The Checkbox colors for checked and unchecked states cannot be controlled from JS at the moment; this PR adds support for that.
The essence of changing colors for the states is this:
```
ColorStateList cls = new ColorStateList(
new int[][] {
new int[] { -android.R.attr.state_checked }, // unchecked
new int[] { android.R.attr.state_checked } // checked
},
new int[] {
uncheckedColor,
checkedColor
}
);
checkBox.setSupportButtonTintList(cls);
```
Because of this, I did it so that both colors have to provided together in an object. This is similar to [switch](https://facebook.github.io/react-native/docs/switch#trackcolor)
Pull Request resolved: https://github.com/facebook/react-native/pull/18300
Differential Revision: D14180218
Pulled By: cpojer
fbshipit-source-id: 88a9d1faf061c0651e3e28950f697535b90fbfd4
976f4be457