DevTools: InspectorView.lockCurrentPanel implementation.

When a profiler starts recording a profile it disables other agents.
As a result the other panels may flip into an unworkable state.
So we would like to stick the user to the profiler panel.

BUG=381115

Review URL: https://codereview.chromium.org/347983003

git-svn-id: svn://svn.chromium.org/blink/trunk@176836 bbb929c8-8fbe-4397-9dbb-9b2b20218538