Make console.profile work after cross-process navigation

Make sure profiler agent enablement state is restored after inspected render process change during navigation.

BUG=None
R=alph@chromium.org

Review URL: https://codereview.chromium.org/23441084

git-svn-id: svn://svn.chromium.org/blink/trunk@158276 bbb929c8-8fbe-4397-9dbb-9b2b20218538