DevTools: Show displayName in popover while paused.

Remove name, inferredName and displayName from Debugger.FunctionDetails struct in favor of functionName calculated in the backend.

BUG=17356
R=yurys@chromium.org

Review URL: https://codereview.chromium.org/52103005

git-svn-id: svn://svn.chromium.org/blink/trunk@161326 bbb929c8-8fbe-4397-9dbb-9b2b20218538