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 41 matching lines @@
    private:
     ChangeType change_;
     FileType file_type_;
   };
 
   class ChangeList {
    public:
     typedef std::deque<Change> List;
 
     ChangeList();
+    ChangeList(const ChangeList& other);
     ~ChangeList();
 
     // Updates the list with the |new_change|.
     void Update(const Change& new_change);
 
     size_t size() const { return list_.size(); }
     bool empty() const { return list_.empty(); }
     void clear() { list_.clear(); }
     const List& list() const { return list_; }
     const Change& front() const { return list_.front(); }
@@ skipping 37 matching lines @@
 
   std::string DebugString() const;
 
  private:
   Map map_;
 };
 
 }  // namespace drive
 
 #endif  // COMPONENTS_DRIVE_FILE_CHANGE_H_