fix isInChromiumDirectory
fix isInChromiumDirectory

Checkout of chromium directory may not have 'chromium'.
e.g.
https://ci.chromium.org/p/devtools-frontend/builders/try/devtools_frontend_linux_blink_light_rel
has chromium checkout under 'builder' dir.

Bug: 1278663
Change-Id: Icaef7e58ba93e30528ae23d352842abd3d0f3055
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3414935
Auto-Submit: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Reviewed-by: Tim Van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>
Commit-Queue: Tim Van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>

ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend