[Sync] Post back to UI thread for USS GetAllNodes.

components/browser_sync/profile_sync_service.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 "components/browser_sync/profile_sync_service.h"
 
 #include <stddef.h>
 
 #include <cstddef>
 #include <map>
@@ skipping 2092 matching lines @@
       const base::Callback<void(std::unique_ptr<base::ListValue>)>& callback);
 
   void OnReceivedNodesForType(const syncer::ModelType type,
                               std::unique_ptr<base::ListValue> node_list);
 
  private:
   friend class base::RefCountedThreadSafe<GetAllNodesRequestHelper>;
   virtual ~GetAllNodesRequestHelper();
 
   std::unique_ptr<base::ListValue> result_accumulator_;
-
   syncer::ModelTypeSet awaiting_types_;
   base::Callback<void(std::unique_ptr<base::ListValue>)> callback_;
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(GetAllNodesRequestHelper);
 };
 
 GetAllNodesRequestHelper::GetAllNodesRequestHelper(
     syncer::ModelTypeSet requested_types,
     const base::Callback<void(std::unique_ptr<base::ListValue>)>& callback)
     : result_accumulator_(new base::ListValue()),
       awaiting_types_(requested_types),
       callback_(callback) {}
 
 GetAllNodesRequestHelper::~GetAllNodesRequestHelper() {
   if (!awaiting_types_.Empty()) {
     DLOG(WARNING)
         << "GetAllNodesRequest deleted before request was fulfilled.  "
         << "Missing types are: " << ModelTypeSetToString(awaiting_types_);
   }
 }
 
 // Called when the set of nodes for a type has been returned.
 // Only return one type of nodes each time.
 void GetAllNodesRequestHelper::OnReceivedNodesForType(
     const syncer::ModelType type,
     std::unique_ptr<base::ListValue> node_list) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
   // Add these results to our list.
   std::unique_ptr<base::DictionaryValue> type_dict(new base::DictionaryValue());
   type_dict->SetString("type", ModelTypeToString(type));
   type_dict->Set("nodes", std::move(node_list));
   result_accumulator_->Append(std::move(type_dict));
 
   // Remember that this part of the request is satisfied.
   awaiting_types_.Remove(type);
 
   if (awaiting_types_.Empty()) {
@@ skipping 298 matching lines @@
     return;
 
   DCHECK(startup_controller_->IsSetupInProgress());
   startup_controller_->SetSetupInProgress(false);
 
   if (IsEngineInitialized())
     ReconfigureDatatypeManager();
   NotifyObservers();
 }
 }  // namespace browser_sync