USS SyncContextProxy / data type activation refactoring

sync/internal_api/sync_context_proxy_impl.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 SYNC_INTERNAL_API_SYNC_CONTEXT_PROXY_IMPL_H_
 #define SYNC_INTERNAL_API_SYNC_CONTEXT_PROXY_IMPL_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/sequenced_task_runner.h"
 #include "sync/base/sync_export.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/sync_context_proxy.h"
 
 namespace syncer_v2 {
-class ModelTypeProcessor;
 class SyncContext;
-struct DataTypeState;
 
 // Encapsulates a reference to the sync context and the thread it's running on.
 // Used by sync's data types to connect with the sync context.
 //
 // It is expected that this object will be copied to and used on many different
 // threads.  It is small and safe to pass by value.
 class SYNC_EXPORT_PRIVATE SyncContextProxyImpl : public SyncContextProxy {
  public:
   SyncContextProxyImpl(
       const scoped_refptr<base::SequencedTaskRunner>& sync_task_runner,
       const base::WeakPtr<SyncContext>& sync_context);
   ~SyncContextProxyImpl() override;
 
   // Attempts to connect a non-blocking type to the sync context.
   //
   // This may fail under some unusual circumstances, like shutdown.  Due to the
   // nature of WeakPtrs and cross-thread communication, the caller will be
   // unable to distinguish a slow success from failure.
-  //
-  // Must be called from the thread where the data type lives.
   void ConnectTypeToSync(
       syncer::ModelType type,
-      const DataTypeState& data_type_state,
-      const UpdateResponseDataList& pending_updates,
-      const base::WeakPtr<ModelTypeProcessor>& type_processor) override;
+      scoped_ptr<ActivationContext> activation_context) override;
 
   // Disables syncing for the given type on the sync thread.
   void Disconnect(syncer::ModelType type) override;
 
   scoped_ptr<SyncContextProxy> Clone() const override;
 
  private:
   // A SequencedTaskRunner representing the thread where the SyncContext lives.
   scoped_refptr<base::SequencedTaskRunner> sync_task_runner_;
 
   // The SyncContext this object is wrapping.
   base::WeakPtr<SyncContext> sync_context_;
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_SYNC_CONTEXT_PROXY_IMPL_H_