[quickview] Add files-ng feature flag to files-metadata-entry

Change-Id: Ifb6a94187b2baa612ce9595bf1e2213c7cf13dc5
Bug: 992824
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2063552Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#742494}

ui/file_manager/file_manager/foreground/elements/files_metadata_entry.js

@@ -22,6 +22,25 @@ const FilesMetadataEntry = Polymer({
       reflectToAttribute: true,
       value: false,
     },
+
+    /**
+     * True if files-ng is enabled.
+     * @const @type {boolean}
+     * @private
+     */
+    filesNg_: {
+      type: Boolean,
+      value: util.isFilesNg(),
+    }
   },
 
+  /**
+   * On element creation, set the files-ng attribute to enable files-ng
+   * specific CSS styling.
+   */
+  created: function() {
+    if (this.filesNg_) {
+      this.setAttribute('files-ng', '');
+    }
+  },
 });