[Sync] Add support for proxy types

chrome/browser/sync/glue/sync_backend_host.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "build/build_config.h"
 
 #include "chrome/browser/sync/glue/sync_backend_host.h"
 
 #include <algorithm>
 #include <map>
@@ skipping 665 matching lines @@
   // downloaded if they are enabled.
   //
   // The SyncBackendRegistrar's state was initially derived from the types
   // detected to have been downloaded in the database.  Afterwards it is
   // modified only by this function.  We expect it to remain in sync with the
   // backend because configuration requests are never aborted; they are retried
   // until they succeed or the backend is shut down.
 
   syncer::ModelTypeSet types_to_download = registrar_->ConfigureDataTypes(
       types_to_add, types_to_remove);
+  types_to_download.RemoveAll(syncer::LocalTypes());

[tim (not reviewing), 2013/01/18 20:56:33]

It looks like most of this CL is actually removing virtual types from places
where they don't match the expectation of the code around it.  Are we really
sure "virtual types" aren't purely a glue/ layer translation concept that don't
need to be plumbed down to the sync engine?

[Nicolas Zea, 2013/01/19 00:03:13]

How do you mean? If we're passing information via the routing info, it has to be
understood by the engine layer.

That said, most of the places being adjusted are tests. I also think I was
prematurely adjusting some of them, and so have slimmed this patch down a bit.

   if (!types_to_download.Empty())
     types_to_download.Put(syncer::NIGORI);
 
   // TODO(sync): crbug.com/137550.
   // It's dangerous to configure types that have progress markers.  Types with
   // progress markers can trigger a MIGRATION_DONE response.  We are not
   // prepared to handle a migration during a configure, so we must ensure that
   // all our types_to_download actually contain no data before we sync them.
   //
   // One common way to end up in this situation used to be types which
@@ skipping 909 matching lines @@
   DVLOG(1) << "Connection status changed: "
            << syncer::ConnectionStatusToString(status);
   frontend_->OnConnectionStatusChange(status);
 }
 
 #undef SDVLOG
 
 #undef SLOG
 
 }  // namespace browser_sync