DevTools: Fix "Show editor in drawer" experiment
DevTools: Fix "Show editor in drawer" experiment

This regressed in r166725

R=vsevik
NOTRY=true

Review URL: https://codereview.chromium.org/157803009

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@166908 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs