tree 1bde1eacfbdc6b3843e5ccaad9772f1bdf180e19
parent 4eba0e18bc2721a8ae32cd62f65e0045af217f89
author Frédéric Wang <fwang@igalia.com> 1674501736 -0800
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> 1674502611 -0800

FontFallbackList::CompositeKey should take current_family->FamilyIsGeneric() into account

FontFallBackList::GetShapeCache calculates the key of a FontDescription
via FontFallbackList::CompositeKey as follows:

1. Initialize the key's data/hash in FallbackListCompositeKey's
  constructor. This ignores FontDescription::family_list_ but takes
  into account FontDescription::generic_family_ via BitmapFields() and
  AuxiliaryBitmapFields().

2. Update key's data/hash via FallbackListCompositeKey::Add and
  FontDescripion::CacheKey for each item of
  FontDescription::family_list_

As a consequence, this calculation is not sufficient to distinguish
FontDescription created from things like font-family: "system-ui"
(quoted) and font-family: system-ui (unquoted) [1] [2]. The
ShapeCache is still used in canvas and so it is possible to tweak
WPT test css/css-fonts/generic-family-keywords-001.html in order to
exhibit that issue.

This CL modifies FontFallbackList::CompositeKey to ensure that
FamilyIsGeneric() is taken into account for each item of
FontDescription::family_list_. It also adds the canvas version of
the corresponding WPT test mentioned above.

[1] The latter specifies a generic font family but the former does not.
    See https://drafts.csswg.org/css-fonts-4/#family-name-syntax
[2] For generic family listed in FontDescription::GenericFamilyType,
    it is necessary to add another generic family to the font-family
    so that they use the same FontDescription::generic_family_.
    For details, see https://docs.google.com/document/d/1nYJzL-MWQrTmf9Z-KscTWuM_5n6-IVdJeEllJ3Appro/edit

Bug: 1408485
Change-Id: Iac95ccf0fd345352cce963f77a60818060a40dc7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4176920
Reviewed-by: Dominik Röttsches <drott@chromium.org>
Commit-Queue: Frédéric Wang <fwang@igalia.com>
Cr-Commit-Position: refs/heads/main@{#1095744}