LazyLoad: Fix lazyloading of pseudo css background styles

This CL passes PseudoElement to StyleResolverState, so that
ElementStyleResources::LoadPendingResources() can listen on the
appropriate pseudo element to defer and lazyload the background image.

(cherry picked from commit 9b78d5ebfc641eb10eb77b335314b1d0273c61e4)

Bug: 950503
Change-Id: Ieab6c4284ac6d405ba49d0d2535d3b05ce95fea2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1632595
Commit-Queue: rajendrant <rajendrant@chromium.org>
Reviewed-by: Fernando Serboncini <fserb@chromium.org>
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#665713}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1642246
Reviewed-by: rajendrant <rajendrant@chromium.org>
Cr-Commit-Position: refs/branch-heads/3809@{#56}
Cr-Branched-From: d82dec1a818f378c464ba307ddd9c92133eac355-refs/heads/master@{#665002}
10 files changed