[Sync] Add plumbing of context from client to server

[Sync] Add plumbing of context from client to server

The datatype context is now written into the directory and plumbed up to the
server on every GetUpdates or Commit request. GetUpdatesResponses also now
overwrite the context if the version returned is the same or higher.

BUG=345420
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=261873

[Nicolas Zea, 2014-04-03 01:00:55]

PTAL. This patch builds off https://codereview.chromium.org/218623014/

[rlarocque, 2014-04-03 17:31:58]

Some comments from the first pass.

https://codereview.chromium.org/215973007/diff/1/chrome/browser/sync/glue/gen...
File chrome/browser/sync/glue/generic_change_processor.cc (right):

https://codereview.chromium.org/215973007/diff/1/chrome/browser/sync/glue/gen...
chrome/browser/sync/glue/generic_change_processor.cc:162: return
syncer::SyncError();  // Context already matches.
Why is this an error?  It seems harmless.

https://codereview.chromium.org/215973007/diff/1/sync/engine/directory_commit...
File sync/engine/directory_commit_contribution.cc (right):

https://codereview.chromium.org/215973007/diff/1/sync/engine/directory_commit...
sync/engine/directory_commit_contribution.cc:56: sync_pb::DataTypeContext
context;
The entities were grabbed out of the directory while a transaction was active in
the Build() function.  Would it make more sense to grab this state at that time,
too, so that we know they're in sync?

https://codereview.chromium.org/215973007/diff/1/sync/engine/directory_update...
File sync/engine/directory_update_handler.cc (right):

https://codereview.chromium.org/215973007/diff/1/sync/engine/directory_update...
sync/engine/directory_update_handler.cc:52: void
DirectoryUpdateHandler::ProcessDataTypeContextMutation(
Does the context need to be updated atomically with the progress markers?  If
so, then this should be merged into ProcessGetUpdatesResponse.

[Nicolas Zea, 2014-04-03 22:56:46]

PTAL. I've moved some the SetDataTypeContext logic into the WriteTransaction,
since the generic change processor doesn't really need to know about directories
and BaseWriteTransaction's.

+Nick FYI

https://codereview.chromium.org/215973007/diff/1/chrome/browser/sync/glue/gen...
File chrome/browser/sync/glue/generic_change_processor.cc (right):

https://codereview.chromium.org/215973007/diff/1/chrome/browser/sync/glue/gen...
chrome/browser/sync/glue/generic_change_processor.cc:162: return
syncer::SyncError();  // Context already matches.
On 2014/04/03 17:31:58, rlarocque wrote:
> Why is this an error?  It seems harmless.

default-initialized SyncError aren't errors.

https://codereview.chromium.org/215973007/diff/1/sync/engine/directory_commit...
File sync/engine/directory_commit_contribution.cc (right):

https://codereview.chromium.org/215973007/diff/1/sync/engine/directory_commit...
sync/engine/directory_commit_contribution.cc:56: sync_pb::DataTypeContext
context;
On 2014/04/03 17:31:58, rlarocque wrote:
> The entities were grabbed out of the directory while a transaction was active
in
> the Build() function.  Would it make more sense to grab this state at that
time,
> too, so that we know they're in sync?

Done.

https://codereview.chromium.org/215973007/diff/1/sync/engine/directory_update...
File sync/engine/directory_update_handler.cc (right):

https://codereview.chromium.org/215973007/diff/1/sync/engine/directory_update...
sync/engine/directory_update_handler.cc:52: void
DirectoryUpdateHandler::ProcessDataTypeContextMutation(
On 2014/04/03 17:31:58, rlarocque wrote:
> Does the context need to be updated atomically with the progress markers?  If
> so, then this should be merged into ProcessGetUpdatesResponse.

Done.

[rlarocque, 2014-04-03 23:13:35]

lgtm

[Nicolas Zea, 2014-04-04 04:56:25]

The CQ bit was checked by zea@chromium.org

[commit-bot: I haz the power, 2014-04-04 04:56:34]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/zea@chromium.org/215973007/40001

[commit-bot: I haz the power, 2014-04-04 06:28:32]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-04-04 06:28:32]

Try jobs failed on following builders:
  tryserver.chromium on linux_chromium_chromeos_rel

[Nicolas Zea, 2014-04-04 18:01:22]

The CQ bit was checked by zea@chromium.org

[commit-bot: I haz the power, 2014-04-04 18:02:17]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/zea@chromium.org/215973007/60001

[commit-bot: I haz the power, 2014-04-04 19:36:03]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-04-04 19:36:03]

Try jobs failed on following builders:
  tryserver.chromium on linux_chromium_rel

[Nicolas Zea, 2014-04-04 19:37:25]

The CQ bit was checked by zea@chromium.org

[commit-bot: I haz the power, 2014-04-04 19:38:27]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/zea@chromium.org/215973007/60001

[commit-bot: I haz the power, 2014-04-04 21:10:29]

Change committed as 261873