DevTools: Fix platform-specific extension-based shortcuts on Windows
DevTools: Fix platform-specific extension-based shortcuts on Windows

TBR=vsevik
BUG=357494

Review URL: https://codereview.chromium.org/216693003

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@170327 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