Material 3 - Regular chip and Action chip templates using invalid tokens #141288
Description
Steps to reproduce
To reproduce run the gen_defaults tool (#140872 improves some false positives and the output)
Here is the result:
Filter chip and input chip token usages are being fixed in #140573
The assist-chip token (called ActionChip in Flutter) is being referenced in both the chip_template and the action_chip_template files.
More specifically, the token is referenced for the checkmarkColor and deleteIconColor values. Since the gen tool was reading non existing tokens, the resulting value is a null color.
Action Chip
To fix the action chip template I propose the following:
deleteIconColor
Action chips don't have an onDeleted callback in the Flutter API, so we could leave the value explicitly as null
checkmarkColor
We could do the same here, because action chips in the Flutter API cannot be selected and they don't have a showCheckmark parameter. Alternatively we can use the same tokens as the leading icon. Any of the solutions would result in the same output, as there is an iconTheme above the leading icon, which takes the correct token already.
(Regular) Chip
The regular Chip template is taking the token values from the assist-chip specification. This can fall short when we try to pick values from the assist-chip spec for the delete and the checkmark icons.
To fix the chip template I propose the following:
deleteIconColor
For this type of chip, Flutter provides an onDeleted callback, so we need to find an appropiate token. The problem is that assist-chip doesn't contemplate having a trailing icon, only a leading icon with the primary color. So if we would use assist-chip icon color, it would turn the delete icon purple/pink instead of dark grey (default Material 3 theme). I propose that we change the chip template to read from filter-chip instead, which is more general, contemplating the possibility of a leading icon and a trailing icon (delete/dropdown) with appropriate colors.
Changing the base of the chip template with filter-chip doesn't really have much changes visually. The delete icon color would go from black to (onSurfaceVariant) dark grey in a light theme. The leading icon color stays the same, as well as the chip borders.
checkmarkColor
Same as the Action Chip proposed changes.
Common changes
Same as #140573 we can update the label color with the correct token. The color token for the label is not currently being used.
Regular chip visual differences
A regular Chip would change as follows. Essentially, black -> dark grey (onSurfaceVariant) for both the label and the delete icon.
Before
After (picture from the M3 spec)
Ignore the icon difference. Flutter picks a different delete icon for the regular Chip.
