Currently Chromite uses gsutil to talk to Google Storage. The GS team has changed their policy, and are now encouraging users to use their API directly.

We should consider implementing our own client as a library.

Advantages:
 * Connection pooling to improve performance (reduced authentication).
 * More precise error feedback/handling.

Disadvantages:
 * Will destabilize something that's currently stable.
 * Must reimplement a large number of advanced GS features.
 * Must directly support going forward.