| Index: third_party/WebKit/LayoutTests/custom-elements/spec/resources/custom-elements-helpers.js | 
| diff --git a/third_party/WebKit/LayoutTests/custom-elements/spec/resources/custom-elements-helpers.js b/third_party/WebKit/LayoutTests/custom-elements/spec/resources/custom-elements-helpers.js | 
| index 7a1c7196fe65276e536e5b269001cb878089c62f..114e1b00bc6ffb268a28a110e75a443962c4ef7d 100644 | 
| --- a/third_party/WebKit/LayoutTests/custom-elements/spec/resources/custom-elements-helpers.js | 
| +++ b/third_party/WebKit/LayoutTests/custom-elements/spec/resources/custom-elements-helpers.js | 
| @@ -4,7 +4,7 @@ function create_window_in_test(t, srcdoc) { | 
| f.srcdoc = srcdoc ? srcdoc : ''; | 
| f.onload = (event) => { | 
| let w = f.contentWindow; | 
| -      t.add_cleanup(() => f.remove()); | 
| +      t.add_cleanup(() => f.parentNode && f.remove()); | 
| resolve(w); | 
| }; | 
| document.body.appendChild(f); | 
|  |