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

chrome/browser/media_galleries/media_file_system_registry.cc

 // 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.
 
 #include "chrome/browser/media_galleries/media_file_system_registry.h"
 
 #include <stddef.h>
 
 #include <set>
 #include <vector>
@@ skipping 257 matching lines @@
     : name(fs_name),
       path(fs_path),
       fsid(filesystem_id),
       pref_id(pref_id),
       transient_device_id(transient_device_id),
       removable(removable),
       media_device(media_device) {
 }
 
 MediaFileSystemInfo::MediaFileSystemInfo() {}
+MediaFileSystemInfo::MediaFileSystemInfo(const MediaFileSystemInfo& other) =
+    default;
 MediaFileSystemInfo::~MediaFileSystemInfo() {}
 
 // The main owner of this class is
 // |MediaFileSystemRegistry::extension_hosts_map_|, but a callback may
 // temporarily hold a reference.
 class ExtensionGalleriesHost
     : public base::RefCountedThreadSafe<ExtensionGalleriesHost> {
  public:
   // |no_references_callback| is called when the last WebContents reference
   // goes away. WebContents references are added through
@@ skipping 591 matching lines @@
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   auto extension_hosts_it = extension_hosts_map_.find(profile);
   DCHECK(extension_hosts_it != extension_hosts_map_.end());
   extension_hosts_map_.erase(extension_hosts_it);
 
   auto profile_subscription_it = profile_subscription_map_.find(profile);
   DCHECK(profile_subscription_it != profile_subscription_map_.end());
   profile_subscription_map_.erase(profile_subscription_it);
 }