GitLab

setNeedsActiveStyleUpdate checks if the document is active before
calling markTreeScopeDirty. This avoids marking shadow root tree scopes
dirty for non-active documents which caused a DCHECK fail in
markTreeScopeDirty.

R=esprehn@chromium.org
BUG=676441

Review-Url: https://codereview.chromium.org/2611053004
Cr-Commit-Position: refs/heads/master@{#442028}