Import wpt@b937003be3ffa2391a355c04b2672183d6b73db4

Using wpt-import in Chromium 525bd4d1.
With Chromium commits locally applied on WPT:
23705631 "service worker: Upstream sandboxed iframe test to WPT."


Build: https://build.chromium.org/p/chromium.infra.cron/builders/wpt-importer/builds/5671

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=lukebjerring

No-Export: true
Change-Id: I9e1a633a388916def7cb1c2d0aece50d5df7c5eb
Reviewed-on: https://chromium-review.googlesource.com/777904
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@{#517827}

third_party/WebKit/LayoutTests/external/wpt/css/cssom/getComputedStyle-pseudo-expected.txt

@@ -5,5 +5,6 @@ PASS Resolution of nonexistent pseudo-element styles
 PASS Resolution of pseudo-element styles in display: none elements
 PASS Item-based blockification of pseudo-elements
 FAIL Item-based blockification of nonexistent pseudo-elements assert_equals: Pseudo-styles of display: flex elements should get blockified expected "block" but got "inline"
+PASS display: contents on pseudo-elements
 Harness: the test ran to completion.
 

third_party/WebKit/LayoutTests/external/wpt/css/cssom/getComputedStyle-pseudo.html

@@ -38,12 +38,19 @@
 #flex-no-pseudo {
   display: flex;
 }
+#contents-pseudos::before,
+#contents-pseudos::after {
+  display: contents;
+  content: "foo";
+  position: absolute;
+}
 </style>
 <div id="test">
   <div id="contents"></div>
   <div id="none"></div>
   <div id="flex"></div>
   <div id="flex-no-pseudo"></div>
+  <div id="contents-pseudos"></div>
 </div>
 <script>
 test(function() {
@@ -91,4 +98,15 @@ test(function() {
                   "Pseudo-styles of display: flex elements should get blockified");
   });
 }, "Item-based blockification of nonexistent pseudo-elements");
+test(function() {
+  var contentsPseudos = document.getElementById('contents-pseudos');
+  [":before", ":after"].forEach(function(pseudo) {
+    assert_equals(getComputedStyle(contentsPseudos, pseudo).display, "contents",
+                  "display: contents in " + pseudo + " should get reflected on CSSOM");
+    assert_equals(getComputedStyle(contentsPseudos, pseudo).width, "auto",
+                  pseudo + " with display: contents should have no box");
+    assert_equals(getComputedStyle(contentsPseudos, pseudo).position, "absolute",
+                  "display: contents in " + pseudo + " should reflect other non-inherited properties in CSSOM");
+  });
+}, "display: contents on pseudo-elements");
 </script>