Add width=device-width,initial-scale=1 to avoid auto shrink the contents to intersection-observer tests. Differential Revision: https://phabricator.services.mozilla.com/D31580 bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1552134 gecko-commit: a6e9e91432d4c224cef1ea0b8c232ccd4c57dd13 gecko-integration-branch: autoland gecko-reviewers: emilio 
diff --git a/intersection-observer/same-document-root.html b/intersection-observer/same-document-root.html index 40467be..bfb9b72 100644 --- a/intersection-observer/same-document-root.html +++ b/intersection-observer/same-document-root.html 
@@ -1,4 +1,5 @@  <!DOCTYPE html> +<meta name="viewport" content="width=device-width,initial-scale=1">  <script src="/resources/testharness.js"></script>  <script src="/resources/testharnessreport.js"></script>  <script src="./resources/intersection-observer-test-utils.js"></script>