Also add a superclass to BasicWorkspace and PubWorkspace, since the bulk of their
implementation is shared; Only find() and findPackageFor() need to be separate;
the package mapping and resolving can be shared.
Change-Id: I13932d6947d6dc28fc7223594e5bd2526f12f573
Reviewed-on: https://dart-review.googlesource.com/c/89167
Commit-Queue: Samuel Rawlins <srawlins@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Sam Rawlins
b58aa3bcb2