I though I'd give more specifics, in case it helps.
I created a (trivial) web-app, and deployed it to my 'testers'. This
worked.
I set up an API Console project, and selected 'Drive API' and 'Drive
SDK' services. I also completed the forms in 'Drive SDK' and 'API
Access' sections.
I then updated my manifest.json by incrementing the version, and
adding these two properties:
"container" : "GOOGLE_DRIVE",
"api_console_project_id" : "<my-12-digit-project-id-from-drive-sdk-
section-of-API-Console>",
I think reupload the zip for my app with this new manifest, and that
works OK, however, when I try and 'Publish to Test Accounts', I now
get this error:
* This item is not allowed to link to the API console project
specified in the manifest. You may only link to an API Console project
if one of the owners of your Chrome Webstore project is a writer or
owner of the API Console project.