[Sync] Remove unneeded 'using syncer::' lines and 'syncer::' scopings

sync/internal_api/js_mutation_event_observer.h

 // 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.
 
 #ifndef SYNC_INTERNAL_API_JS_MUTATION_EVENT_OBSERVER_H_
 #define SYNC_INTERNAL_API_JS_MUTATION_EVENT_OBSERVER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/non_thread_safe.h"
 #include "sync/internal_api/public/sync_manager.h"
 #include "sync/internal_api/public/util/weak_handle.h"
 #include "sync/syncable/transaction_observer.h"
 
 namespace tracked_objects {
 class Location;
 }  // namespace tracked_objects
 
 namespace syncer {
 
 class JsEventDetails;
 class JsEventHandler;
 
 // Observes all change- and transaction-related events and routes a
 // summarized version to a JsEventHandler.
 class JsMutationEventObserver
-    : public syncer::SyncManager::ChangeObserver,
+    : public SyncManager::ChangeObserver,
       public syncable::TransactionObserver,
       public base::NonThreadSafe {
  public:
   JsMutationEventObserver();
 
   virtual ~JsMutationEventObserver();
 
   base::WeakPtr<JsMutationEventObserver> AsWeakPtr();
 
   void InvalidateWeakPtrs();
 
   void SetJsEventHandler(const WeakHandle<JsEventHandler>& event_handler);
 
-  // syncer::SyncManager::ChangeObserver implementation.
+  // SyncManager::ChangeObserver implementation.
   virtual void OnChangesApplied(
-      syncer::ModelType model_type,
+      ModelType model_type,
       int64 write_transaction_id,
-      const syncer::ImmutableChangeRecordList& changes) OVERRIDE;
-  virtual void OnChangesComplete(syncer::ModelType model_type) OVERRIDE;
+      const ImmutableChangeRecordList& changes) OVERRIDE;
+  virtual void OnChangesComplete(ModelType model_type) OVERRIDE;
 
   // syncable::TransactionObserver implementation.
   virtual void OnTransactionWrite(
       const syncable::ImmutableWriteTransactionInfo& write_transaction_info,
-      syncer::ModelTypeSet models_with_changes) OVERRIDE;
+      ModelTypeSet models_with_changes) OVERRIDE;
 
  private:
   base::WeakPtrFactory<JsMutationEventObserver> weak_ptr_factory_;
   WeakHandle<JsEventHandler> event_handler_;
 
   void HandleJsEvent(
     const tracked_objects::Location& from_here,
     const std::string& name, const JsEventDetails& details);
 
   DISALLOW_COPY_AND_ASSIGN(JsMutationEventObserver);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_JS_MUTATION_EVENT_OBSERVER_H_