[LongTaskV2] Fix flakiness in longtask-v8compile test

The original test is flaky in both virtual test and nonvirtual test.

For the non-virtual test, it was expected to fail for one reason but it's
reasonable to fail for other reasons as well. We should include those failures.

For the virtual test, the test failed since long tasks could be present in a
slow environment. We fix it by ignoring those longtasks & attributions that are
not generated by us. Also, we allow waiting for multiple entry lists until we
find the interesting one.

Bug: 775626
Change-Id: Ief2a3bc4016dc3f808cb17be0122e35f75b58f9a
Reviewed-on: https://chromium-review.googlesource.com/891571
Commit-Queue: Liquan Gu <maxlg@chromium.org>
Reviewed-by: Timothy Dresser <tdresser@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533016}

third_party/WebKit/LayoutTests/TestExpectations

@@ -1684,6 +1684,9 @@ crbug.com/711529 http/tests/workers/shared-worker-performance-timeline.html [ Ti
 # This test requires enabling the flag CustomUserTiming in a virtual test.
 crbug.com/758385 http/tests/performance-timing/custom-user-timing/po-customusertiming-mark.html [ Skip ]
 
+# This test requires enabling the flag LongTaskV2 in a virtual test suite.
+crbug.com/738493 http/tests/performance-timing/longtask-v2/longtask-v8compile.html [ Skip ]
+
 # Expected failures during incremental implementation of mojo notification.
 crbug.com/595685 virtual/mojo-notifications/http/tests/notifications/close-dedicated-worker.html [ Skip ]
 crbug.com/595685 virtual/mojo-notifications/http/tests/notifications/close-dispatch-asynchronous.html [ Skip ]
@@ -3204,8 +3207,6 @@ crbug.com/774463 [ Win7 Debug ] fast/events/autoscroll-should-not-stop-on-keypre
 crbug.com/774463 [ Win7 Debug ] virtual/mouseevent_fractional/fast/events/autoscroll-should-not-stop-on-keypress.html [ Failure Pass ]
 crbug.com/774688 [ Mac ] fast/spatial-navigation/snav-container-white-space.html [ Pass Failure ]
 
-crbug.com/776201 [ Win7 Debug ] virtual/longtask-v2/http/tests/performance-timing/longtask-v2/longtask-v8compile.html [ Pass Failure ]
-
 # Sheriff failures 2017-10-23
 crbug.com/772411 http/tests/media/autoplay-crossorigin.html [ Timeout Failure Pass ]
 crbug.com/777222 http/tests/devtools/change-iframe-src.js [ Pass Failure Timeout ]

third_party/WebKit/LayoutTests/http/tests/performance-timing/longtask-v2/longtask-v8compile-expected.txt

-This is a testharness.js-based test.
-FAIL Performance longtask entries with script-compile attribute are observable. assert_false: script-compile is not captured. expected false got true
-Harness: the test ran to completion.
-

third_party/WebKit/LayoutTests/http/tests/performance-timing/longtask-v2/longtask-v8compile.html

@@ -10,12 +10,20 @@
 <div id="log"></div>
 <script>
   async_test(function (t) {
+    const scriptURL = 'resources/makelongtask.js';
+    const lineColumn = '(0, 0)';
     const observer = new PerformanceObserver(
-      t.step_func(function (entryList) {
-        const entries = entryList.getEntries();
-        assert_equals(entries.length, 1,
-            'Exactly one entry is expected.');
-        const longtask = entries[0];
+      t.step_func(function(entryList) {
+        const longtaskEntries = entryList.getEntries().filter((e) => {
+          return e.attribution.find((a) => {
+            return a.scriptURL.includes(scriptURL);
+          });
+        });
+        if (longtaskEntries.length === 0) {
+          return;
+        }
+        assert_equals(longtaskEntries.length, 1);
+        const longtask = longtaskEntries[0];
         assert_equals(longtask.entryType, 'longtask');
         assert_equals(longtask.name, 'self');
         assert_greater_than(longtask.duration, 50);
@@ -23,17 +31,19 @@
         const currentTime = performance.now();
         assert_less_than_equal(longtask.startTime, currentTime);
 
-        const it = longtask.attribution.find(function(it) {
-          return it.name === 'script-compile';
+        const compileAttribution = longtask.attribution.filter((it) => {
+          return it.name === 'script-compile' &&
+              it.scriptURL.includes(scriptURL);
         });
-        assert_false(!it, 'script-compile is not captured.');
+        assert_equals(compileAttribution.length, 1);
+        const it = compileAttribution[0];
         assert_greater_than(it.startTime, 0);
         assert_equals(it.entryType, 'taskattribution');
         assert_equals(it.containerType, 'iframe');
         assert_equals(it.containerId, '');
         assert_equals(it.containerName, '');
         assert_equals(it.containerSrc, '');
-        assert_true(it.scriptURL.includes('resources/makelongtask.js(0, 0)'));
+        assert_true(it.scriptURL.includes(scriptURL + lineColumn));
         observer.disconnect();
         t.done();
       })