Update media galleries scan results, even when zero.

chrome/browser/media_galleries/media_galleries_preferences.cc

Index: chrome/browser/media_galleries/media_galleries_preferences.cc
diff --git a/chrome/browser/media_galleries/media_galleries_preferences.cc b/chrome/browser/media_galleries/media_galleries_preferences.cc
index 006fee9410088ea74cb195a5892b0868a3e82893..fbc809db8e7f35ee2965c5619cc34dad5313bc65 100644
--- a/chrome/browser/media_galleries/media_galleries_preferences.cc
+++ b/chrome/browser/media_galleries/media_galleries_preferences.cc
@@ -823,7 +823,8 @@ MediaGalleryPrefId MediaGalleriesPreferences::AddGalleryInternal(
     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)