Call preventDefault in all on-tap events that show a dialog.

chrome/browser/resources/settings/reset_page/reset_page.js

 // Copyright 2015 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.
 
 /**
  * @fileoverview
  * 'settings-reset-page' is the settings page containing reset
  * settings.
  *
  * Example:
@@ skipping 44 matching lines @@
     settings.navigateTo(settings.Route.RESET_DIALOG,
                         new URLSearchParams('origin=userclick'));
   },
 
   /** @private */
   onResetProfileDialogClose_: function() {
     settings.navigateToPreviousRoute();
   },
 
 <if expr="chromeos">
-  /** @private */
-  onShowPowerwashDialog_: function() {
+  /**
+   * @param {!Event} e
+   * @private
+   */
+  onShowPowerwashDialog_: function(e) {
+    e.preventDefault();
     this.showPowerwashDialog_ = true;
   },
 
   /** @private */
   onPowerwashDialogClose_: function() {
     this.showPowerwashDialog_ = false;
   },
 </if>
 });