DevTools: inspector.css is concatenated twice in release mode.
DevTools: inspector.css is concatenated twice in release mode.

BUG=309481
TBR=vsevik

Review URL: https://codereview.chromium.org/72393003

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@162019 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