Enable "SetTimeoutWithoutClamp" flag on the field trial testing

And add unit tests to cover disable/enable flags using a
`ScopedFeatureList`.

This is a follow-up to the intent-to-ship of removing clamp in
setTimeout(...,0), see
https://groups.google.com/a/chromium.org/g/blink-dev/c/HKPTp7C1LwY/m/5Rl78YJfAwAJ

NOTE TO SHERRIFS:
  If any tests are flaky, please help to change setTimeout(..., 0)
  to setTimeout(..., 1) if it can be found in a test that regressed
  before reverting this CL. Otherwise please disable the test and
  assign the bug to me, I'll dig more.

Bug: 402694

Change-Id: I436dcb6bb4a8ed43844cd0833bf0ef82528b0a95
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3243793
Reviewed-by: Scott Haseley <shaseley@chromium.org>
Reviewed-by: Nate Chapin <japhet@chromium.org>
Commit-Queue: Wanming Lin <wanming.lin@intel.com>
Cr-Commit-Position: refs/heads/main@{#944816}

testing/variations/fieldtrial_testing_config.json

@@ -7137,6 +7137,28 @@
             ]
         }
     ],
+    "SetTimeoutWithoutClamp": [
+        {
+            "platforms": [
+                "android",
+                "android_weblayer",
+                "android_webview",
+                "chromeos",
+                "ios",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "SetTimeoutWithoutClamp"
+                    ]
+                }
+            ]
+        }
+    ],
     "SettingsResetPrompt": [
         {
             "platforms": [

third_party/blink/renderer/core/frame/dom_timer_test.cc

@@ -4,8 +4,10 @@
 
 #include "third_party/blink/renderer/core/frame/dom_timer.h"
 
+#include "base/test/scoped_feature_list.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/blink/public/common/features.h"
 #include "third_party/blink/renderer/bindings/core/v8/idl_types.h"
 #include "third_party/blink/renderer/bindings/core/v8/native_value_traits_impl.h"
 #include "third_party/blink/renderer/bindings/core/v8/script_source_code.h"
@@ -93,9 +95,12 @@ const char* const kSetTimeout0ScriptText =
     "}"
     "setTimeout(setTimeoutCallback, 0);";
 
-TEST_F(DOMTimerTest, DISABLED_setTimeout_ZeroIsNotClampedToOne) {
+TEST_F(DOMTimerTest, setTimeout_ZeroIsNotClampedToOne) {
   v8::HandleScope scope(v8::Isolate::GetCurrent());
 
+  base::test::ScopedFeatureList feature_list;
+  feature_list.InitAndEnableFeature(features::kSetTimeoutWithoutClamp);
+
   ExecuteScriptAndWaitUntilIdle(kSetTimeout0ScriptText);
 
   double time = ToDoubleValue(EvalExpression("elapsed"), scope);
@@ -103,6 +108,19 @@ TEST_F(DOMTimerTest, DISABLED_setTimeout_ZeroIsNotClampedToOne) {
   EXPECT_THAT(time, DoubleNear(0., kThreshold));
 }
 
+TEST_F(DOMTimerTest, setTimeout_ZeroIsClampedToOne) {
+  v8::HandleScope scope(v8::Isolate::GetCurrent());
+
+  base::test::ScopedFeatureList feature_list;
+  feature_list.InitAndDisableFeature(features::kSetTimeoutWithoutClamp);
+
+  ExecuteScriptAndWaitUntilIdle(kSetTimeout0ScriptText);
+
+  double time = ToDoubleValue(EvalExpression("elapsed"), scope);
+
+  EXPECT_THAT(time, DoubleNear(1., kThreshold));
+}
+
 const char* const kSetTimeoutNestedScriptText =
     "var last = performance.now();"
     "var times = [];"

third_party/blink/web_tests/TestExpectations

@@ -7349,6 +7349,13 @@ crbug.com/1272203 external/wpt/websockets/stream/tentative/backpressure-send.any
 # Times out flakily on all platforms. Previously marked slow, crbug.com/874695.
 crbug.com/1272801 http/tests/permissions/chromium/test-request-sharedworker.html [ Pass Timeout ]
 
+# Flaky with setTimeout without clamp
+crbug.com/1272954 external/wpt/app-history/currentchange-event/currentchange-app-history-navigate-same-doc.html [ Failure Pass ]
+crbug.com/1272954 external/wpt/app-history/currentchange-event/currentchange-app-history-back-forward-same-doc.html [ Failure Pass ]
+crbug.com/1272954 external/wpt/app-history/currentchange-event/currentchange-history-back-same-doc.html [ Failure Pass ]
+crbug.com/1272954 external/wpt/app-history/navigate-event/navigate-history-back-after-fragment.html [ Failure Pass ]
+crbug.com/1272955 http/tests/devtools/extensions/extensions-timeline-api.js [ Failure Pass ]
+
 # Sheriff 2021-11-23
 crbug.com/1270963 wpt_internal/fenced_frame/create-credential.https.html [ Skip ]
 crbug.com/1046784 http/tests/devtools/tracing/timeline-receive-response-event.js [ Failure Pass ]

third_party/blink/web_tests/external/wpt/html/webappapis/update-rendering/child-document-raf-order-expected.txt

@@ -1,4 +1,4 @@
 This is a testharness.js-based test.
-FAIL Ordering of steps in "Update the Rendering" - child document requestAnimationFrame order assert_array_equals: expected order of notifications lengths differ, expected array ["parent_raf", "first_child_raf", "second_child_raf"] length 3, got ["parent_raf", "second_child_raf", "first_child_raf", "parent_raf", "second_child_raf", "first_child_raf"] length 6
+FAIL Ordering of steps in "Update the Rendering" - child document requestAnimationFrame order assert_array_equals: expected order of notifications expected property 1 to be "first_child_raf" but got "second_child_raf" (expected array ["parent_raf", "first_child_raf", "second_child_raf"] got ["parent_raf", "second_child_raf", "first_child_raf"])
 Harness: the test ran to completion.