Change a FrameSelection::setSelectedRange argument type from bool to enum.

Let's use FrameSelection::DirectoinalOption instead of bool.


BUG=

Review URL: https://codereview.chromium.org/328243004

git-svn-id: svn://svn.chromium.org/blink/trunk@176192 bbb929c8-8fbe-4397-9dbb-9b2b20218538