DevTools: handle InspectorFrontendHost.inspectedURLChanged on browser side (Blink part).

R=vsevik@chromium.org

Review URL: https://codereview.chromium.org/278583003

git-svn-id: svn://svn.chromium.org/blink/trunk@173635 bbb929c8-8fbe-4397-9dbb-9b2b20218538