portage: Make install_deps return a struct

This is a refactoring CL to make it easier to add a new field.

BUG=b:261863720
TEST=BOARD=amd64-generic bazel build @portage//target/dev-libs/libgcrypt

Change-Id: I9d1ba0efd167c783deeba22f2619dd3d37cc0681
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/bazel/+/5370140
Tested-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Shuhei Takahashi <nya@chromium.org>
Commit-Queue: Raul Rangel <rrangel@chromium.org>
3 files changed