[EventTiming] Attempt to fix some flaky tests

This CL attempts to fix test flakiness.
* For the click counts, remove tests about mouseout/mouseover since
those could fail under certain starting positions of the mouse, and
the test has a pretty high flakiness score right now.
* For other tests, fix flakiness by making sure that PerformanceObserver
callbacks where mousedown is not present are ignored. This is possible
since a click triggers mousedown, mouseup, click, etc., so we cannot
just assume that mousedown will always be present at the callback.

Bug: 1074048
Change-Id: I95a082948c105cf18b51376c9d6421195b23b718
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2163775Reviewed-by: Yoav Weiss <yoavweiss@chromium.org>
Commit-Queue: Nicolás Peña Moreno <npm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#763352}

third_party/blink/web_tests/external/wpt/event-timing/crossiframe.html

@@ -51,13 +51,18 @@
   promise_test(async t => {
     assert_implements(window.PerformanceEventTiming, "Event Timing is not supported");
     clickTimeMin = performance.now();
-    let observedEntries = false;
+    let observedMouseDown = false;
     const observerPromise = new Promise(resolve => {
       new PerformanceObserver(t.step_func(entries => {
-        assert_false(observedEntries,
+        const mouseDowns = entries.getEntriesByName('mousedown');
+        // Ignore the callback if there were no mousedown entries.
+        if (mouseDowns.length === 0)
+          return;
+
+        assert_false(observedMouseDown,
             "Observer of main frames should only capture main-frame event-timing entries");
-        validateEntries(entries.getEntriesByName('mousedown'));
-        observedEntries = true;
+        validateEntries(mouseDowns);
+        observedMouseDown = true;
         resolve();
       })).observe({type: 'event'});
     });

third_party/blink/web_tests/external/wpt/event-timing/event-click-counts.html

@@ -22,10 +22,6 @@
       assert_equals(clickCount, expectedCount,'Incorrect click count.');
       assert_equals(performance.eventCounts.get('mousedown'), expectedCount, 'Incorrect mousedown count');
       assert_equals(performance.eventCounts.get('mouseup'), expectedCount, 'Incorrect mouseup count.');
-      assert_equals(performance.eventCounts.get('mouseover'), expectedCount, 'Incorrect mouseover count.');
-      if (expectedCount != 1) {
-        assert_equals(performance.eventCounts.get('mouseout'), expectedCount - 1, 'Incorrect mouseout count.');
-      }
       resolve();
     }
     function promiseClicks(expectedCount) {

third_party/blink/web_tests/external/wpt/event-timing/event-retarget.html

@@ -23,12 +23,16 @@ async_test(function(t) {
       };
     }
   });
-  const observer = new PerformanceObserver(t.step_func_done((entryList) => {
-    const entries = entryList.getEntries().filter(e => e.name === 'mousedown');
-    // There must only be one click entry.
+  const observer = new PerformanceObserver(t.step_func((entryList) => {
+    const entries = entryList.getEntriesByName('mousedown');
+    if (entries.length === 0)
+      return;
+
+    // There must only be one mousedown entry.
     assert_equals(entries.length, 1);
     verifyClickEvent(entries[0], 'custom_button', true);
     assert_true(innerButtonClicked);
+    t.done()
   }));
   observer.observe({entryTypes: ['event']});
   clickAndBlockMain('custom_button');

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

@@ -17,25 +17,35 @@
     while(performance.now() < end) {}
     delayCalled = true;
   }
-  async_test(function(t) {
+  promise_test(function(t) {
     assert_implements(window.PerformanceEventTiming, 'Event Timing is not supported.');
-    const observer = new PerformanceObserver(t.step_func_done((entryList) => {
-      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);
-      verifyClickEvent(entry, 'div2', true);
-    }));
-    observer.observe({entryTypes: ['event']});
+    let observedMouseDown = false;
+    const observerPromise = new Promise(resolve => {
+      const observer = new PerformanceObserver(t.step_func(entryList => {
+        const mouseDowns = entryList.getEntriesByName('mousedown');
+        // Ignore cases in which there is no mousedown.
+        if (mouseDowns.length === 0)
+          return;
+
+        assert_false(observedMouseDown, 'There must only be one mousedown entry.');
+        assert_equals(mouseDowns.length, 1);
+        const entry = mouseDowns[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);
+        verifyClickEvent(entry, 'div2', true);
+        observedMouseDown = true;
+        resolve();
+      }));
+      observer.observe({entryTypes: ['event']});
+    });
     document.getElementById('div').click();
     // Take the timestamp after the programmatic click but before the next click.
     beforeClick = performance.now();
     // After the programmatic click, use another input to know when entries have been
     // dispatched to the PerformanceObserver callback.
-    clickAndBlockMain('div2');
+    const clickPromise = clickAndBlockMain('div2');
+    return Promise.all([observerPromise, clickPromise]);
   }, "Event Timing: events from programmatic click are not observed");
 </script>
 </html>

third_party/blink/web_tests/external/wpt/event-timing/retrievability.html

@@ -31,9 +31,11 @@
   */
   async_test(function(t) {
     assert_implements(window.PerformanceEventTiming, 'Event Timing is not supported.');
-    new PerformanceObserver(t.step_func_done(() => {
-      validateEntries();
-      t.done();
+    new PerformanceObserver(t.step_func(entryList => {
+      if (entryList.getEntriesByName('mousedown')) {
+        validateEntries();
+        t.done();
+      }
     })).observe({entryTypes: ['event']});
     clickAndBlockMain('button');
   }, "Event Timing: make sure event-timing entries are not retrievable by performance.getEntries*.");

third_party/blink/web_tests/external/wpt/event-timing/timingconditions.html

@@ -32,28 +32,38 @@
     target.focus();
   }
 
-  async_test(function(t) {
+  promise_test(function(t) {
     assert_implements(window.PerformanceEventTiming, 'Event Timing is not supported.');
-    new PerformanceObserver(t.step_func_done(entryList => {
-      const observerCallbackTime = performance.now();
-      const entries = entryList.getEntries().filter(
-          entry => entry.name === 'mousedown');
-      assert_equals(entries.length, 1,
-          "Should only observe one entry: " +
-          JSON.stringify(entries) + ".");
-      assert_equals(entries[0].name, 'mousedown',
-          "The observed entry should be a click");
-      assert_less_than(entries[0].startTime, observerCallbackTime,
-          "The startTime should be before observerCallbackTime");
-      assert_greater_than(entries[0].startTime, trustedClickStart,
-          "The startTime should be after trustedClickStart");
-    })).observe({ entryTypes: ['event'] });
+    let observedMouseDown = false;
+    const observerPromise = new Promise(resolve => {
+      new PerformanceObserver(t.step_func(entryList => {
+        const observerCallbackTime = performance.now();
+        const mouseDowns = entryList.getEntriesByName('mousedown');
+        // Ignore cases in which there is no mousedown.
+        if (mouseDowns.length === 0)
+          return;
+
+        assert_false(observedMouseDown, 'Got more than one callback with mousedown.');
+        assert_equals(mouseDowns.length, 1,
+            "Should only observe one mousedown entry. Instead, got these: " +
+            JSON.stringify(mouseDowns) + ".");
+        assert_equals(mouseDowns[0].name, 'mousedown',
+            "The observed entry should be a mousedown");
+        assert_less_than(mouseDowns[0].startTime, observerCallbackTime,
+            "The startTime should be before observerCallbackTime");
+        assert_greater_than(mouseDowns[0].startTime, trustedClickStart,
+            "The startTime should be after trustedClickStart");
+        observedMouseDown = true;
+        resolve();
+      })).observe({ entryTypes: ['event'] });
+    });
     // Untrusted event of a type event timing cares about.
     untrustedClickAndBlockMain('button');
     // Trusted event of a type event timing doesn't cares about.
     trustedFocusAndBlockMain('button');
     // Trusted event of a type event timing cares about.
-    trustedClickAndBlockMain('button').then(wait);
+    const clickPromise = trustedClickAndBlockMain('button').then(wait);
+    return Promise.all([observerPromise, clickPromise]);
   }, "Event Timing only times certain types of trusted event.");
 </script>
 </html>