Reland "[EventTiming] Fix programmatic click test"

This is a reland of 3bd9684

The failure was not getting an entry for click:
https://ci.chromium.org/p/chromium/builders/ci/Mac10.13%20Tests/13241

Thus, we instead look at the mousedown. Since mousedown can be the first
input, we stop observing for firstInput but check that entry separately
as well.

Original change's description:
> [EventTiming] Fix programmatic click test
>
> Commits aee8357 and
> faed29a landed almost at the same time,
> so we accidentally landed a test with the wrong script src for the
> helper functions.
>
> Bug: 961547
> Change-Id: Id8a615477a54e56139d9d90fc4feb5f780b729a2
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1606225
> Reviewed-by: Liquan (Max) Gu <maxlg@chromium.org>
> Commit-Queue: Nicolás Peña Moreno <npm@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#658761}

Bug: 961547
Change-Id: I11f1a5f28e7e4e5ebda28c90555d89669142cc09
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1610022
Reviewed-by: Liquan (Max) Gu <maxlg@chromium.org>
Commit-Queue: Nicolás Peña Moreno <npm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#659680}

third_party/blink/web_tests/TestExpectations

@@ -5562,9 +5562,6 @@ crbug.com/959129 [ Win Linux ] http/tests/devtools/tracing/timeline-script-parse
 # Sheriff 2019-05-07
 crbug.com/960443 [ Mac10.10 Mac10.11 ] external/wpt/animation-worklet/worklet-animation-with-scroll-timeline.https.html [ Failure Pass ]
 
-# Sheriff 2019-05-07
-crbug.com/961547 external/wpt/event-timing/programmatic-click-not-observed.html [ Pass Failure ]
-
 # Sheriff 2019-05-10
 crbug.com/960623 [ Win ] http/tests/misc/resource-timing-sizes-multipart.html [ Pass Failure ]
 

third_party/blink/web_tests/external/wpt/event-timing/programmatic-click-not-observed.html

@@ -8,7 +8,7 @@
 <script src=/resources/testdriver.js></script>
 <script src=/resources/testdriver-vendor.js></script>
 
-<script src=resources/event-timing-support.js></script>
+<script src=resources/event-timing-test-utils.js></script>
 <script>
   let delayCalled = false;
   let beforeClick;
@@ -19,15 +19,19 @@
   }
   async_test(function(t) {
     const observer = new PerformanceObserver(t.step_func_done((entryList) => {
-      const entries = entryList.getEntries().filter(e => e.name === 'click');
+      const entries = entryList.getEntries().filter(e => e.name === 'mousedown');
       // There must only be one click entry: from the clickAndBlockMain() call.
       assert_equals(entries.length, 1);
       const entry = entries[0];
       // This ensures that the entry is exposing timing from the second click, i.e.
       // the one from the clickAndBlockMain() call.
       assert_greater_than_equal(entry.processingStart, beforeClick);
+      // Check that the first input entry was also from the second click.
+      const firstInput = performance.getEntriesByType('firstInput');
+      assert_equals(firstInput.length, 1);
+      assert_greater_than_equal(firstInput[0].processingStart, beforeClick);
     }));
-    observer.observe({entryTypes: ['firstInput', 'event']});
+    observer.observe({entryTypes: ['event']});
     document.getElementById('div').click();
     // Take the timestamp after the programmatic click but before the next click.
     beforeClick = performance.now();