components: Add out-of-line copy ctors for complex classes.

components/drive/file_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 COMPONENTS_DRIVE_FILE_CHANGE_H_
 #define COMPONENTS_DRIVE_FILE_CHANGE_H_
 
 #include <stddef.h>
 
 #include <deque>
@@ skipping 66 matching lines @@
     std::string DebugString() const;
 
    private:
     List list_;
   };
 
  public:
   typedef std::map<base::FilePath, FileChange::ChangeList> Map;
 
   FileChange();
+  FileChange(const FileChange& other);
   ~FileChange();
 
   void Update(const base::FilePath file_path,
               const FileChange::Change& new_change);
   void Update(const base::FilePath file_path,
               const FileChange::ChangeList& list);
   void Update(const base::FilePath file_path,
               FileType type,
               FileChange::ChangeType change);
   void Update(const base::FilePath file_path,
@@ skipping 13 matching lines @@
 
   std::string DebugString() const;
 
  private:
   Map map_;
 };
 
 }  // namespace drive
 
 #endif  // COMPONENTS_DRIVE_FILE_CHANGE_H_