Add

tag to grid templates in generated canvas tests

Since an explicit tag wasn't present in the template for variant
grids, it was not possible to attach and remove children from
document.body. This is working already for offscreen tests that don't
use grids, since the

tag they use to place the test name creates
an implicit . This change adds this same

tag to both grid
templates.

In a follow-up CL in the stack, this tag is used to compare via assert
values calculated from a Canvas Text API to their counterpart from text
placed in the DOM.

Bug: 341213359
Change-Id: Id9d084adc261195601b0b9748e2bc0df5b8b0b59
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5593277
Reviewed-by: Jean-Philippe Gravel jpgravel@chromium.org
Commit-Queue: Andres Ricardo Perez andresrperez@chromium.org
Cr-Commit-Position: refs/heads/main@{#1322182}