Quick View: avoid to lose focus when metadata button is clicked.

ui/file_manager/file_manager/foreground/elements/files_quick_view.js

 // Copyright 2016 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.
 
 var FilesQuickView = Polymer({
   is: 'files-quick-view',
 
   properties: {
     // File media type, e.g. image, video.
     type: String,
@@ skipping 61 matching lines @@
   },
 
   /**
    * Client should assign the function to open the file.
    *
    * @param {!Event} event
    */
   onOpenInNewButtonTap: function(event) {},
 
   /**
+   * @param {!Event} event tap event.
+   *
+   * @private
+   */
+  onMetadataButtonTap_: function(event) {
+    // Set focus back to innerContent panel so that pressing space key next
+    // closes Quick View.
+    this.$.innerContentPanel.focus();
+  },
+
+  /**
    * Close Quick View unless the clicked target or its ancestor contains
    * 'no-close-on-click' class.
    *
    * @param {!Event} event tap event.
    *
    * @private
    */
   onContentPanelTap_: function(event) {
     var target = event.detail.sourceEvent.target;
     while (target) {
@@ skipping 49 matching lines @@
    * @param {string} type
    * @return {boolean}
    *
    * @private
    */
   isUnsupported_: function(type) {
     return !this.isImage_(type) && !this.isVideo_(type) && !this.isAudio_(type);
   },
 
 });