Resolve internal forced colors properties before used value time

This CL moves the re-resolution of internal forced colors properties
(specifically 'internal-forced-color', 'internal-forced-visited-color'
and 'internal-forced-background-color') to occur before used value
time. This is necessary because work is being done to remove system
colors from being stored in the NativeTheme to being accessed from
color providers that are associated with the Page(see CL:4898493). To
access the color providers, we need to pass them from the document to
the LayoutTheme::SystemColor method.

However, this is problematic in StyleColor::Resolve, where we currently
pass a boolean flag(`is_forced_colors`) to resolve the initial values
for these forced color properties at used value time(see: CL:2529950).
This was done because the initial values for these properties are
defined as system colors in css_properties.json5
(e.g. StyleColor(CSSValueID::kCanvas)). These values are only computed
once, so we need to recompute them to ensure they pick up the correct
color on theme change.

We want to remove this flag to avoid resolving any system colors at
used value time, which will allow us to pass nullptr instead of a color
provider when resolving colors in StyleColor::Resolve, since we do not
have an easy way to access the provider at this point in the rendering
pipeline.

To solve this, we re-resolve the initial values of these properties in
the StyleAdjuster class to avoid the need for re-resolution at used
value time. Also, we propagate the `internal-forced-background-color`
from the root to the viewport when forced colors is enabled.

Bug: 1430181
Change-Id: I5c12bff59c8ae7d760ffc34dd6d4d2d050bf0019
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5181788
Reviewed-by: Anders Hartvoll Ruud <andruud@chromium.org>
Reviewed-by: Alison Maher <almaher@microsoft.com>
Commit-Queue: Sam Davis Omekara <samomekarajr@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#1258657}

• third_party/blink/renderer/core/css/properties/longhands/longhands_custom.cc[diff]
• third_party/blink/renderer/core/css/resolver/style_adjuster.cc[diff]
• third_party/blink/renderer/core/css/resolver/style_adjuster.h[diff]
• third_party/blink/renderer/core/css/resolver/style_resolver.cc[diff]
• third_party/blink/renderer/core/css/style_color.cc[diff]
• third_party/blink/renderer/core/css/style_color.h[diff]
• third_party/blink/renderer/core/style/computed_style.cc[diff]