s/resolverIfExists/resolver and s/styleResolverIfExists/styleResolver.

This is more consistent with our naming conventions in the rest of the codebase.

Review URL: https://codereview.chromium.org/102693004

git-svn-id: svn://svn.chromium.org/blink/trunk@163138 bbb929c8-8fbe-4397-9dbb-9b2b20218538