https://uberchromegw.corp.google.com/i/internal.tryserver.clankium/builders/arm-builder-tester/builds/1628

[W2018-07-10T15:11:34.936640-07:00 25743 0 auth.go:1032] Failed to read auth token from cache: invalid service account credentials
[E2018-07-10T15:11:34.936659-07:00 25743 0 service.go:91] Failed to load private key JSON - open /creds/service_accounts/service-account-clank-internal-builder.json: no such file or directory
isolate: isolate Contains call failed: gave up after 11 attempts: Post https://chrome-isolated.appspot.com/_ah/api/isolateservice/v1/preupload: invalid service account credentials
step returned non-zero exit code: 1