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

chrome/common/importer/imported_bookmark_entry.cc

 // 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.
 
 #include "chrome/common/importer/imported_bookmark_entry.h"
 
 ImportedBookmarkEntry::ImportedBookmarkEntry()
     : in_toolbar(false),
       is_folder(false) {}
 
+ImportedBookmarkEntry::ImportedBookmarkEntry(
+    const ImportedBookmarkEntry& other) = default;
+
 ImportedBookmarkEntry::~ImportedBookmarkEntry() {}
 
 bool ImportedBookmarkEntry::operator==(
     const ImportedBookmarkEntry& other) const {
   return (in_toolbar == other.in_toolbar &&
           is_folder == other.is_folder &&
           url == other.url &&
           path == other.path &&
           title == other.title &&
           creation_time == other.creation_time);
 }