QuickView: Add labels and tabindex for accessibility.

ui/file_manager/file_manager/foreground/js/quick_view_controller.js

Index: ui/file_manager/file_manager/foreground/js/quick_view_controller.js
diff --git a/ui/file_manager/file_manager/foreground/js/quick_view_controller.js b/ui/file_manager/file_manager/foreground/js/quick_view_controller.js
index c45fe1562d069c56abcf0fd542ef621b0929f61e..5cd58fc415f3cd8a3861841cffded62cb001fa87 100644
--- a/ui/file_manager/file_manager/foreground/js/quick_view_controller.js
+++ b/ui/file_manager/file_manager/foreground/js/quick_view_controller.js
@@ -69,6 +69,10 @@ function QuickViewController(
       'keydown', this.onKeyDownToOpen_.bind(this));
   quickView.addEventListener('keydown', this.onQuickViewKeyDown_.bind(this));
   quickView.onOpenInNewButtonTap = this.onOpenInNewButtonTap_.bind(this);
+
+  var toolTip = this.quickView_.$$('files-tooltip');
+  var elems = this.quickView_.$.buttons.querySelectorAll('[has-tooltip]');
+  toolTip.addTargets(elems);
 }
 
 /**