[Sync] Support open tabs experiment enabling before sync setup completion.

chrome/browser/sync/glue/sync_backend_host.cc

 // Copyright (c) 2011 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 802 matching lines @@
   SVLOG(1) << "Got snapshot " << snapshot->ToString();
 
   const syncable::ModelTypeSet& to_migrate =
       snapshot->syncer_status.types_needing_local_migration;
   if (!to_migrate.empty())
     host_->frontend_->OnMigrationNeededForTypes(to_migrate);
 
   // Process any changes to the datatypes we're syncing.
   // TODO(sync): add support for removing types.
   syncable::ModelTypeSet to_add;
-  if (host_->initialized() &&
-      sync_manager()->ReceivedExperimentalTypes(&to_add)) {
+  if (sync_manager()->ReceivedExperimentalTypes(&to_add)) {

[akalin, 2011/10/14 23:18:48]

hmm.  Thinking about this, I think it's cleaner to just cache to_add if not
initialized yet and call OnDataTypesChanged after we do initialize (in
HandleInitializationCompleteOnFrontendLoop).  I'm wary of making some functions
callable when uninitialized and some not.  Although it's a pain because it would
add an extra member variable and have two places to do the same thing.

Maybe have a helper fn:

SBH::AddExperimentalTypes() {
  CHECK(initialized());
  ModelTypeSet to_add;
  if (sync_manager()->Received..()) {
    frontend_->OnDataTypesChanged(...);
  }
}

and then here:

if (host->initialized()) {
  host->AddExperimentalTypes();
}

and in HandleInitializationCompleteOnFrontendLoop:

case REFRESHING_ENCRYPTION:
  initialization_state_ = INITIALIZED;
  frontend_->OnBackendInitialized(...);
  AddExperimentalTypes();

[Nicolas Zea, 2011/10/15 00:31:35]

Done.

     host_->frontend_->OnDataTypesChanged(to_add);
   }
 
   // If we are waiting for a configuration change, check here to see
   // if this sync cycle has initialized all of the types we've been
   // waiting for.
   if (host_->pending_download_state_.get()) {
     scoped_ptr<PendingConfigureDataTypesState> state(
         host_->pending_download_state_.release());
     DCHECK(
@@ skipping 201 matching lines @@
       FROM_HERE,
       base::Bind(&SyncBackendHost::Core::DoRefreshEncryption,
                  core_.get(), sync_thread_done_callback));
 }
 
 #undef SVLOG
 
 #undef SLOG
 
 }  // namespace browser_sync