Files.app: Mark RAW files as filename-hidable files.

BUG=486911
TEST=Check if filenames are hidden for RAW files in a directory which hold only RAW files.

Review URL: https://codereview.chromium.org/1137343003

Cr-Commit-Position: refs/heads/master@{#330034}

ui/file_manager/file_manager/foreground/js/ui/file_grid.js

@@ -593,7 +593,8 @@ FileGrid.prototype.decorateThumbnailBox_ = function(li, entry) {
     box.setAttribute('generic-thumbnail', mediaType);
     li.classList.toggle('thumbnail-loaded', false);
   }
-  li.classList.toggle('can-hide-filename', FileType.isImage(entry));
+  li.classList.toggle('can-hide-filename',
+                      FileType.isImage(entry) || FileType.isRaw(entry));
 };
 
 /**