Import wpt@5b68d219206139c0bfeec65c88e765749aed57fb

Using wpt-import in Chromium cce37ea2.

Build: https://ci.chromium.org/buildbot/chromium.infra.cron/wpt-importer/15286

Note to sheriffs: This CL imports external tests and adds
expectations for those tests; if this CL is large and causes
a few new failures, please fix the failures by adding new
lines to TestExpectations rather than reverting. See:
https://chromium.googlesource.com/chromium/src/+/master/docs/testing/web_platform_tests.md

TBR=ajuma

No-Export: true
Change-Id: I410afda3411e51dc56a5e2f089135be2afd83f0a
Reviewed-on: https://chromium-review.googlesource.com/991412
Commit-Queue: Blink WPT Bot <blink-w3c-test-autoroller@chromium.org>
Reviewed-by: Blink WPT Bot <blink-w3c-test-autoroller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547615}

third_party/WebKit/LayoutTests/external/wpt/custom-elements/custom-element-registry/upgrade.html

@@ -145,10 +145,13 @@ test(() => {
 
   customElements.upgrade(template.content);
 
-  assert_true(el1 instanceof Element1, "element 1 must now be upgraded");
-  assert_true(el2 instanceof Element2, "element 2 must now be upgraded");
-  assert_true(el3 instanceof Element3, "element 3 must now be upgraded");
-  assert_true(el4 instanceof Element4, "element 4 must now be upgraded");
-  assert_true(el5 instanceof Element5, "element 5 must now be upgraded");
+  // Template contents owner documents don't have a browsing context, so
+  // https://html.spec.whatwg.org/multipage/custom-elements.html#look-up-a-custom-element-definition does not find any
+  // custom element definition.
+  assert_false(el1 instanceof Element1, "element 1 must still not be upgraded after upgrading the template contents");
+  assert_false(el2 instanceof Element2, "element 2 must still not be upgraded after upgrading the template contents");
+  assert_false(el3 instanceof Element3, "element 3 must still not be upgraded after upgrading the template contents");
+  assert_false(el4 instanceof Element4, "element 4 must still not be upgraded after upgrading the template contents");
+  assert_false(el5 instanceof Element5, "element 5 must still not be upgraded after upgrading the template contents");
 }, "Elements inside a template contents DocumentFragment node");
 </script>