Import Cobalt 19.master.0.203780

Includes the following patches:
  https://cobalt-review.googlesource.com/c/cobalt/+/5210
    by errong.leng@samsung.com
  https://cobalt-review.googlesource.com/c/cobalt/+/5270
    by linus.wang@samsung.com
diff --git a/src/third_party/web_platform_tests/custom-elements/resources/blank.html b/src/third_party/web_platform_tests/custom-elements/resources/blank.html
new file mode 100644
index 0000000..2e5697b
--- /dev/null
+++ b/src/third_party/web_platform_tests/custom-elements/resources/blank.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <title>Blank document</title>
+    <link rel="author" title="Aleksei Yu. Semenov" href="mailto:a.semenov@unipro.ru">
+</head>
+<body>
+</body>
+</html>