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

chrome/browser/media_galleries/media_scan_manager.cc

 // Copyright 2014 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_scan_manager.h"
 
 #include <stddef.h>
 
 #include "base/files/file_enumerator.h"
 #include "base/files/file_util.h"
@@ skipping 445 matching lines @@
   for (ContainerCandidates::const_iterator it = candidates.begin();
        it != candidates.end();
        ++it) {
     if (it->second.is_qualified && it->second.seen_count >= 2)
       result[it->first] = MediaGalleryScanResult();
   }
   return result;
 }
 
 MediaScanManager::ScanObservers::ScanObservers() : observer(NULL) {}
+MediaScanManager::ScanObservers::ScanObservers(const ScanObservers& other) =
+    default;
 MediaScanManager::ScanObservers::~ScanObservers() {}
 
 void MediaScanManager::OnExtensionUnloaded(
     content::BrowserContext* browser_context,
     const extensions::Extension* extension,
     extensions::UnloadedExtensionInfo::Reason reason) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   CancelScan(Profile::FromBrowserContext(browser_context), extension);
 }
 
@@ skipping 71 matching lines @@
                                                            gallery_count,
                                                            file_counts);
       }
     }
     scanning_extensions->clear();
     preferences->SetLastScanCompletionTime(base::Time::Now());
   }
   scoped_extension_registry_observer_.RemoveAll();
   folder_finder_.reset();
 }