Don't assume so easily that RenderStyle data can be shared.

An element can only share RenderStyle data with another element if
BOTH are cacheable. The element that's already in the cache is
obviously cacheable, but we also need to figure out whether the
element that wants to use data from the cache is cachable.

Additionally, get rid of the Element* argument from
applyMatchedProperties(), since it's already part of the state object
passed to that method.

BUG=236329

Review URL: https://chromiumcodereview.appspot.com/20560008

git-svn-id: svn://svn.chromium.org/blink/trunk@154999 bbb929c8-8fbe-4397-9dbb-9b2b20218538