Settings should not call into inspector

Settings should not call into inspector,
rather inspector should cache original setting
and just change setting when required.

BUG=327476

Review URL: https://codereview.chromium.org/146683003

git-svn-id: svn://svn.chromium.org/blink/trunk@166295 bbb929c8-8fbe-4397-9dbb-9b2b20218538