Media Galleries API Metadata: Rename MediaFileSystemMetadata callback.

Just to disambiguate metadata callback for file systems vs. media files.

BUG=318450

Review URL: https://codereview.chromium.org/102723003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238523 0039d316-1c4b-4281-b951-d872f2087c98

chrome/common/extensions/api/media_galleries.idl

@@ -50,7 +50,7 @@ namespace mediaGalleries {
     boolean isAvailable;
   };
 
-  callback MediaGalleriesMetadataCallback =
+  callback MediaFileSystemsMetadataCallback =
       void (MediaFileSystemMetadata[] metadata);
 
   interface Functions {
@@ -65,7 +65,7 @@ namespace mediaGalleries {
 
     // Get metadata for all available media galleries.
     static void getAllMediaFileSystemMetadata(
-        MediaGalleriesMetadataCallback callback);
+        MediaFileSystemsMetadataCallback callback);
   };
 
 };