commit f19e45939b3a068dd72ae9a9b7b554c201cafe9d
author Ivan Pilat <ivanpi@google.com> Wed Jun 22 13:29:37 2016 -0700
committer Ivan Pilat <ivanpi@google.com> Wed Jun 22 13:29:37 2016 -0700
tree 2f06028d3386eb77504e69b4493dde41fe4fcbf7
parent 01e5bffea12e6693af63bdc8e54cc1a37247db4d

syncbase: Send initial root update in Watch.

An empty update for the root entity is sent as the first update on the
watch stream.
* For watches from an empty resume marker, this update is propagated to
the client as part of the initial state batch. It is necessary because
the initial state batch may not contain other updates (if the watch
filter matches no collections) and the client needs to be notified of
this. It is intended to be filtered out by the high-level API when
the initial state batch is being separated out.
* For watches from 'now' or a specific resume marker, the initial update
is sent with initial_state_skipped for compliance with
v.io/v23/services/watch. It is filtered out by the client library
instead of propagating to the user.

Initial update was hooked up end-to-end in Go. Only row updates are
propagated in Java and Cgo for now.

Errors in watch code have also been scrubbed to prevent leaking info
to the client before the authorization step.

MultiPart: 2/4
Change-Id: Iddd43cf73742e14ca8f66818016d6e3ef890b28c