Move local frame-only methods out of WebFrame.

This CL is just cleaning up new methods that were added after the OOPI
work began.

BUG=416656,416658,416659

Review URL: https://codereview.chromium.org/595713002

git-svn-id: svn://svn.chromium.org/blink/trunk@182568 bbb929c8-8fbe-4397-9dbb-9b2b20218538