merge_pr_46388

Fix Null Dereference in css_parsing_utils

This CL addresses a null pointer dereference issue within the
ConsumeColorContrast functions located in css_parsing_utils.cc.
Previously, a null dereference occurred when the code attempted to
retrieve the color provider when the document was null. To resolve
this, the updated code now includes a validation check to ensure the
document object is valid before calling the GetColorProviderForPainting
method.

Bug: 337069153
Change-Id: Ieee6c0e3602b25e8b149c93643e4d55265e4467c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5497219
Reviewed-by: Alison Maher almaher@microsoft.com
Commit-Queue: Sam Davis Omekara samomekarajr@microsoft.com
Cr-Commit-Position: refs/heads/main@{#1304551}