Revert of [Sync] Stop accessing BrowserContextKeyedServiceFactory on non-UI thread.

components/sync/driver/shared_change_processor.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_SYNC_DRIVER_SHARED_CHANGE_PROCESSOR_H_
 #define COMPONENTS_SYNC_DRIVER_SHARED_CHANGE_PROCESSOR_H_
 
 #include <memory>
 #include <string>
 
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/sequenced_task_runner.h"
 #include "base/single_thread_task_runner.h"
 #include "base/synchronization/lock.h"
 #include "components/sync/driver/data_type_controller.h"
-#include "components/sync/driver/sync_client.h"
 #include "components/sync/engine/model_safe_worker.h"
 #include "components/sync/model/data_type_error_handler.h"
 #include "components/sync/model/sync_change_processor.h"
 #include "components/sync/model/sync_data.h"
 #include "components/sync/model/sync_error.h"
 #include "components/sync/model/sync_error_factory.h"
 #include "components/sync/model/sync_merge_result.h"
 
 namespace syncer {
 
 class ChangeProcessor;
 class GenericChangeProcessor;
 class GenericChangeProcessorFactory;
-class SyncApiComponentFactory;
+class SyncClient;
 class SyncableService;
 struct UserShare;
 
 // A ref-counted wrapper around a GenericChangeProcessor for use with datatypes
 // that don't live on the UI thread.
 //
 // We need to make it refcounted as the ownership transfer from the
 // DataTypeController is dependent on threading, and hence racy. The
 // SharedChangeProcessor should be created on the UI thread, but should only be
 // connected and used on the same thread as the datatype it interacts with.
@@ skipping 11 matching lines @@
     : public base::RefCountedThreadSafe<SharedChangeProcessor> {
  public:
   using StartDoneCallback =
       base::Callback<void(DataTypeController::ConfigureResult start_result,
                           const SyncMergeResult& local_merge_result,
                           const SyncMergeResult& syncer_merge_result)>;
 
   // Create an uninitialized SharedChangeProcessor.
   explicit SharedChangeProcessor(ModelType type);
 
-  void StartAssociation(const StartDoneCallback& start_done,
-                        const SyncClient::ServiceProvider& service_provider,
-                        SyncApiComponentFactory* driver_factory,
+  void StartAssociation(StartDoneCallback start_done,
+                        SyncClient* const sync_client,
                         GenericChangeProcessorFactory* processor_factory,
                         UserShare* user_share,
                         std::unique_ptr<DataTypeErrorHandler> error_handler);
 
   // Connect to the Syncer and prepare to handle changes for |type|. Will
   // create and store a new GenericChangeProcessor and return a weak pointer to
   // the SyncableService associated with |type|.
   // Note: If this SharedChangeProcessor has been disconnected, or the
-  // SyncableService is not alive, will return a null weak pointer.
+  // SyncableService was not alive, will return a null weak pointer.
   virtual base::WeakPtr<SyncableService> Connect(
-      const SyncClient::ServiceProvider& service_provider,
-      SyncApiComponentFactory* driver_factory,
+      SyncClient* sync_client,
       GenericChangeProcessorFactory* processor_factory,
       UserShare* user_share,
       std::unique_ptr<DataTypeErrorHandler> error_handler,
       const base::WeakPtr<SyncMergeResult>& merge_result);
 
   // Disconnects from the generic change processor. This method is thread-safe.
   // After this, all attempts to interact with the change processor by
   // |local_service_| are dropped and return errors. The syncer will be safe to
   // shut down from the point of view of this datatype.
   // Note: Once disconnected, you cannot reconnect without creating a new
@@ skipping 69 matching lines @@
   // The local service for this type. Only set if the DTC for the type uses
   // SharedChangeProcessor::StartAssociation().
   base::WeakPtr<SyncableService> local_service_;
 
   DISALLOW_COPY_AND_ASSIGN(SharedChangeProcessor);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_DRIVER_SHARED_CHANGE_PROCESSOR_H_