Update media galleries scan results, even when zero.

chrome/browser/media_galleries/media_galleries_preferences.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_galleries_preferences.h"
 
 #include "base/base_paths_posix.h"
 #include "base/callback.h"
 #include "base/i18n/time_formatting.h"
 #include "base/path_service.h"
@@ skipping 805 matching lines @@
     bool update_gallery_metadata = volume_metadata_valid &&
         ((existing.volume_label != volume_label) ||
          (existing.vendor_name != vendor_name) ||
          (existing.model_name != model_name) ||
          (existing.total_size_in_bytes != total_size_in_bytes) ||
          (existing.last_attach_time != last_attach_time));
 
     bool update_scan_counts =
       new_type != MediaGalleryPrefInfo::kRemovedScan &&
       new_type != MediaGalleryPrefInfo::kBlackListed &&
-      (audio_count > 0 || image_count > 0 || video_count > 0);
+      (audio_count > 0 || image_count > 0 || video_count > 0 ||
+       existing.audio_count || existing.image_count || existing.video_count);
 
     if (!update_gallery_name && !update_gallery_type &&
         !update_gallery_metadata && !update_scan_counts)
       return *pref_id_it;
 
     PrefService* prefs = profile_->GetPrefs();
     scoped_ptr<ListPrefUpdate> update(
         new ListPrefUpdate(prefs, prefs::kMediaGalleriesRememberedGalleries));
     base::ListValue* list = update->Get();
 
@@ skipping 406 matching lines @@
   if (extension_prefs_for_testing_)
     return extension_prefs_for_testing_;
   return extensions::ExtensionPrefs::Get(profile_);
 }
 
 void MediaGalleriesPreferences::SetExtensionPrefsForTesting(
     extensions::ExtensionPrefs* extension_prefs) {
   DCHECK(IsInitialized());
   extension_prefs_for_testing_ = extension_prefs;
 }