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

components/favicon_base/favicon_usage_data.h

 // Copyright 2013 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_FAVICON_BASE_FAVICON_USAGE_DATA_H_
 #define COMPONENTS_FAVICON_BASE_FAVICON_USAGE_DATA_H_
 
 #include <set>
 #include <vector>
 
 #include "url/gurl.h"
 
 namespace favicon_base {
 
 // Used to correlate favicons to imported bookmarks.
 struct FaviconUsageData {
   FaviconUsageData();
+  FaviconUsageData(const FaviconUsageData& other);
   ~FaviconUsageData();
 
   // The URL of the favicon.
   GURL favicon_url;
 
   // The raw png-encoded data.
   std::vector<unsigned char> png_data;
 
   // The list of URLs using this favicon.
   std::set<GURL> urls;
 };
 
 typedef std::vector<FaviconUsageData> FaviconUsageDataList;
 
 }  // namespace favicon_base
 
 #endif  // COMPONENTS_FAVICON_BASE_FAVICON_USAGE_DATA_H_