Revert "DevTools: [Styles] Bring up suggest box for empty property values automatically"

This reverts commit e09d79bc732be6e43c39fb27f979c9676fa3710b.

TBR=vsevik

Review URL: https://codereview.chromium.org/18295006

git-svn-id: svn://svn.chromium.org/blink/trunk@154125 bbb929c8-8fbe-4397-9dbb-9b2b20218538