Description

This fixes several problems with the delete button on Chip widgets:

• Before this, the hit area for the delete button was always 1/3 of the chip size, leading to hit areas that are too wide on large chips, and too small on small chips. This modifies that so that on large chips, it takes up to 28 pixels to the left (in LTR locales, right on RTL) of the center of the delete button (basically a 48x48 square around the delete button, but clipped by the Chip), but is at a minimum up to the left edge of the delete button of the chip on small chips.
• The ripple on the delete button was not being fired in all situations, and when it was, it was clipped to the 16x16 delete icon, making it almost invisible. Now it expands towards the center of the delete button, and stops just short of the edge of the chip.
• The delete button didn't have a focus node, so couldn't be accessed via the keyboard focus traversal. Now it has a focus node again.
• Fixes a small iteration issue in the mock canvas that was throwing an exception instead of showing where the draw operations differed.

This change does not revert to having two ripples for a delete press: there is still only one, since the hit testing separates the delete button InkWell from the main chip (i.e. it doesn't regress b/140930220).

Before (clicking on each active area of the chip):

After (clicking on each active area of the chip):

Related Issues

• Fixes Chip delete button tap target is too small. #42455 It is still too small, but getting closer: it at least tries to be 24 pixels on the left side, plus the distance from the center of the chip to the right side of the chip, so closer, but not there yet (about 36 pixels wide by 32 pixels high on most chips). I think this is probably the best we can do without expanding outside of the size of the chip (which would increase the size of the Material, making it visually different).
• Fixes Chip delete button tap target is always 1/3 the width of the whole chip. #43291 Delete button is no longer a fixed ratio.
• Fixes [Chip] Chip with onDeleted but without onPressed has no ripple when tapping delete button. #43534 Chip with no onPressed, but with onDelete now has a ripple.

Tests

• Added a test for the delete button taking up the right amount of the chip.
• Updated tests to allow for more than one InkWell, but still check for a single ripple.
• Added a test to make sure the delete button is focusable.
• Added a test to make sure that chips without onPressed set, but with onDelete set still ripple.