commit 8462ab7e56bec3a3cb0657f59b3273c6a581b732
author Dave Borowitz <dborowitz@google.com> Thu Apr 21 13:48:12 2016 -0400
committer Dave Borowitz <dborowitz@google.com> Fri Apr 22 10:56:17 2016 -0400
tree d93016c805434ad0ef561e738ae9275206448893
parent 76a6f73a16bd478a0b2541461066e3dedb3bd7bb

ChangeRebuilderImpl: Don't try to read old notes value

When we're rebuilding a change, we don't care about what was
previously in its notes, as it might have been corrupt, or had some
other problem. However we do need to read the ChangeNotes in order to
create a ChangeUpdate.

We still want to use a single ChainedReceiveCommands mediated by the
NoteDbUpdateManager, so that we can do a single atomic update from the
old, bad notes SHA-1 to the new SHA-1. A way to achieve both these
goals is to teach ChangeNotes to read its SHA-1 from the same
ChainedReceiveCommands. Since one of the first things we do when
rebuilding a change is to stage the delete of the ref, this will be as
if the ChangeNotes is read from an empty ref, which is exactly what we
want.

Change-Id: I6c64068dc82be466041c69ed3ef55cd01def7dca