commit b6e38123599226a5db37ecc6d72e087973439ae8
author Alan Screen <awscreen@chromium.org> Fri Mar 04 06:59:59 2022
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Fri Mar 04 06:59:59 2022
tree a2c56bceeb053d4eaf373062dd964742d5ba0484
parent 21ea0b6cee6c27eca8a35d8a21e547903f72e999

Skip sandboxing PrintBackendService for known exceptions

For some printer drivers it can be known ahead of time that sandboxing
of the Print Backend Service should be avoided.

Making use of this knowledge rather than relying upon getting an
access-denied error can be important in some cases.  For example, when
trying to start printing of a document on Windows, if it will require
the display of a system dialog to select the file to save to (e.g.,
print to port FILE:) then the call will hang instead of returning an
error.

Introduce a call to determine if a driver for a client type should
automatically avoid being sandboxed.  This is a workaround for the
hanging issue.  This approach might be improved upon if a Windows low
privilege AppContainer (LPAC) can be made to enable the UI to be
displayed, but that is still a work in progress.

TESTED=On Windows print to a driver that saves to file, such as the
`Microsoft Print to PDF`.  This enables the `File Print Output As`
dialog to be displayed instead of the Print Backend Service process
hanging.

Bug: 809738, 1243873
Change-Id: I102a38c311f012c743cd94c3c81a319d14161ed9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3313488
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Alan Screen <awscreen@chromium.org>
Cr-Commit-Position: refs/heads/main@{#977529}