[Sync] Removing duplicated includes between cc and h files.

components/sync/driver/invalidation_adapter.cc

 // 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.
 
 #include "components/sync/driver/invalidation_adapter.h"
 
-#include <string>
-
 namespace browser_sync {
 
 InvalidationAdapter::InvalidationAdapter(
     const syncer::Invalidation& invalidation)
     : invalidation_(invalidation) {}
 
 InvalidationAdapter::~InvalidationAdapter() {}
 
 bool InvalidationAdapter::IsUnknownVersion() const {
   return invalidation_.is_unknown_version();
 }
 
 const std::string& InvalidationAdapter::GetPayload() const {
   return invalidation_.payload();
 }
 
 int64_t InvalidationAdapter::GetVersion() const {
   return invalidation_.version();
 }
 
 void InvalidationAdapter::Acknowledge() {
   invalidation_.Acknowledge();
 }
 
 void InvalidationAdapter::Drop() {
   invalidation_.Drop();
 }
 
 }  // namespace browser_sync