Delete RuleSetAnalyzer, and fold into RuleFeatureSet. It doesn't make sense to have two classes after all.
Later, RuleFeatureSet can be moved into a subdirectory and/or renamed.

BUG=335247
R=esprehn@chromium.org

Review URL: https://codereview.chromium.org/131023010

git-svn-id: svn://svn.chromium.org/blink/trunk@165551 bbb929c8-8fbe-4397-9dbb-9b2b20218538