Fix Picture-in-Picture test with User Activation V2

With User Activation V2, the click activation is carried on to the
following tests since the state is no longer stack-scoped. By
re-ordering tests, this CL makes sure test doesn't fail when User
Activation V2 is enabled.

Bug: 860718
Change-Id: I54ebc6ca2d808323e4b87997b9687c56e2c8606d
Reviewed-on: https://chromium-review.googlesource.com/1244239
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594133}

third_party/WebKit/LayoutTests/external/wpt/picture-in-picture/request-picture-in-picture.html

@@ -9,8 +9,8 @@
 <script>
 promise_test(async t => {
   const video = await loadVideo();
-  return requestPictureInPictureWithTrustedClick(video);
-}, 'request Picture-in-Picture resolves on user click');
+  return promise_rejects(t, 'NotAllowedError', video.requestPictureInPicture());
+}, 'request Picture-in-Picture requires a user gesture');
 
 promise_test(t => {
   const video = document.createElement('video');
@@ -31,6 +31,6 @@ promise_test(async t => {
 
 promise_test(async t => {
   const video = await loadVideo();
-  return promise_rejects(t, 'NotAllowedError', video.requestPictureInPicture());
-}, 'request Picture-in-Picture requires a user gesture');
+  return requestPictureInPictureWithTrustedClick(video);
+}, 'request Picture-in-Picture resolves on user click');
 </script>