Use CSSUrlData in StyleFetchedImage

This means that state doesn't need to be copied, and we can trivially
recreate a CSSImageValue from the StyleFetchedImage by using the helpers
provided by CSSUrlData. It'll also enable fixing the computed value in a
follow-up CL.

Drop CSSUrlData::GetOriginClean() and change the type of the associated
field in the constructor. Prefer the more verbose bool accessor
(IsFromOriginCleanStyleSheet()) and direct copying instead. This reduces
the impedance mismatch a bit when copying CSSUrlData metadata.

Bug: 41473212
Change-Id: I416b89be1630e8b7d069ca852c8057d3eea14e17
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6508961
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/main@{#1456135}