Make ScopedStyleResolver use apply-author-styles of a given element's treescope.

Suppose that a given shadow tree's apply-author-styles is true. Currently rules only in the nesting tree are applicable to elements in the shadow tree. However, rules in all enclosing trees should be applicable.

TEST=No new tests. Rebased the existing one.
BUG=244779

Review URL: https://chromiumcodereview.appspot.com/16194002

git-svn-id: svn://svn.chromium.org/blink/trunk@151709 bbb929c8-8fbe-4397-9dbb-9b2b20218538
5 files changed