sign_official_build: Port google3 changes for COS

As part of the Cusky signing design, we carry custom changes to the script in a fork of vboot_reference repository on
google3. To move the signing behavior from the BC to the BE, we will need
to port those changes from google3 to here.

To make rebasing this change when do we do a ChromeOS rebase easier, we
fork the changes that were made in google3 into a new file,

The custom changes being ported here are the ones made in cl/316911016,
cl/317144168, cl/318860928, cl/318866697 and cl/318866697.

TEST=presubmit; merged signer container with BE container, patched these
changes in and ran the script

Change-Id: I75af70e0b3603d6fdc4ce05ed8383ab8a66e05fb
Reviewed-by: Robert Kolchmeyer <>
Tested-by: Dexter Rivera <>
1 file changed