[Sync] Expose change location in GenericChangeProcessor errors

sync/api/sync_change.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_API_SYNC_CHANGE_H_
 #define SYNC_API_SYNC_CHANGE_H_
 
 #include <iosfwd>
 #include <string>
 #include <vector>
@@ skipping 32 matching lines @@
   // the data.
   // Deletes: Requires valid tag when going to the syncer. Requires valid
   //          specifics when coming from the syncer.
   // Adds, Updates: Require valid tag and specifics when going to the syncer.
   //                Require only valid specifics when coming from the syncer.
   bool IsValid() const;
 
   // Getters.
   SyncChangeType change_type() const;
   SyncData sync_data() const;
+  tracked_objects::Location location() const;
 
   // Returns a string representation of |change_type|.
   static std::string ChangeTypeToString(SyncChangeType change_type);
 
   // Returns a string representation of the entire object. Used for gmock
   // printing method, PrintTo.
   std::string ToString() const;
 
  private:
   tracked_objects::Location location_;
 
   SyncChangeType change_type_;
 
   // An immutable container for the data of this SyncChange. Whenever
   // SyncChanges are copied, they copy references to this data.
   SyncData sync_data_;
 };
 
 // gmock printer helper.
 void PrintTo(const SyncChange& sync_change, std::ostream* os);
 
 }  // namespace syncer
 
 #endif  // SYNC_API_SYNC_CHANGE_H_