Prototype of adding AbortController to addEventListener

I2P: https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/9396JedBBOM

This feature adds a new AbortSignal option, named "signal", to the
options parameter of addEventListener.
This new option can be used to remove the event listener with an
AbortController by calling abort().
More context: https://github.com/whatwg/dom/issues/911

Bug: 1146467
Change-Id: I8ab1b93ec8be859c6876296fda4a9b808253c7d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2527343
Commit-Queue: Joey Arhar <jarhar@chromium.org>
Reviewed-by: Mason Freed <masonfreed@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826659}

third_party/blink/public/mojom/web_feature/web_feature.mojom

@@ -3056,6 +3056,7 @@ enum WebFeature {
   kAdFrameDetected = 3727,
   kMediaStreamTrackGenerator = 3728,
   kMediaStreamTrackProcessor = 3729,
+  kAddEventListenerWithAbortSignal = 3730,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots.

third_party/blink/renderer/core/dom/events/add_event_listener_options.idl

@@ -7,4 +7,5 @@
 dictionary AddEventListenerOptions : EventListenerOptions {
     boolean passive;
     boolean once = false;
+    [RuntimeEnabled=AddEventListenerAbortSignal] AbortSignal signal;
 };

third_party/blink/renderer/core/dom/events/add_event_listener_options_resolved.cc

@@ -18,6 +18,8 @@ AddEventListenerOptionsResolved::AddEventListenerOptionsResolved(
     setPassive(options->passive());
   if (options->hasOnce())
     setOnce(options->once());
+  if (options->hasSignal())
+    setSignal(options->signal());
   // EventListenerOptions
   if (options->hasCapture())
     setCapture(options->capture());

third_party/blink/renderer/core/dom/events/event_target.cc

@@ -40,6 +40,7 @@
 #include "third_party/blink/renderer/bindings/core/v8/js_based_event_listener.h"
 #include "third_party/blink/renderer/bindings/core/v8/js_event_listener.h"
 #include "third_party/blink/renderer/bindings/core/v8/source_location.h"
+#include "third_party/blink/renderer/core/dom/abort_signal.h"
 #include "third_party/blink/renderer/core/dom/events/add_event_listener_options_resolved.h"
 #include "third_party/blink/renderer/core/dom/events/event.h"
 #include "third_party/blink/renderer/core/dom/events/event_dispatch_forbidden_scope.h"
@@ -474,6 +475,8 @@ bool EventTarget::addEventListener(
       resolved_options->setOnce(options->once());
     if (options->hasCapture())
       resolved_options->setCapture(options->capture());
+    if (options->hasSignal())
+      resolved_options->setSignal(options->signal());
     return addEventListener(event_type, event_listener, resolved_options);
   }
 
@@ -530,6 +533,20 @@ bool EventTarget::AddEventListenerInternal(
   bool added = EnsureEventTargetData().event_listener_map.Add(
       event_type, listener, options, &registered_listener);
   if (added) {
+    if (options->signal()) {
+      options->signal()->AddAlgorithm(WTF::Bind(
+          [](EventTarget* event_target, const AtomicString& event_type,
+             const EventListener* listener) {
+            event_target->removeEventListener(event_type, listener);
+          },
+          WrapWeakPersistent(this), event_type, WrapWeakPersistent(listener)));
+      if (const LocalDOMWindow* executing_window = ExecutingWindow()) {
+        if (const Document* document = executing_window->document()) {
+          document->CountUse(WebFeature::kAddEventListenerWithAbortSignal);
+        }
+      }
+    }
+
     AddedEventListener(event_type, registered_listener);
     if (IsA<JSBasedEventListener>(listener) &&
         IsInstrumentedForAsyncStack(event_type)) {

third_party/blink/renderer/core/dom/events/event_target_test.cc

@@ -69,4 +69,19 @@ TEST_F(EventTargetTest, UseCountBeforematch) {
       GetDocument().IsUseCounted(WebFeature::kBeforematchHandlerRegistered));
 }
 
+TEST_F(EventTargetTest, UseCountAbortSignal) {
+  EXPECT_FALSE(
+      GetDocument().IsUseCounted(WebFeature::kAddEventListenerWithAbortSignal));
+  GetDocument().GetSettings()->SetScriptEnabled(true);
+  ClassicScript::CreateUnspecifiedScript(ScriptSourceCode(R"HTML(
+                       const element = document.createElement('div');
+                       const ac = new AbortController();
+                       element.addEventListener(
+                         'test', () => {}, {signal: ac.signal});
+                      )HTML"))
+      ->RunScript(GetDocument().domWindow());
+  EXPECT_TRUE(
+      GetDocument().IsUseCounted(WebFeature::kAddEventListenerWithAbortSignal));
+}
+
 }  // namespace blink

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -133,6 +133,10 @@
       name: "AccessibilityUseAXPositionForDocumentMarkers",
       status: "test",
     },
+    {
+      name: "AddEventListenerAbortSignal",
+      status: "experimental",
+    },
     {
       name: "AddressSpace",
       status: "experimental",

third_party/blink/web_tests/external/wpt/dom/abort/addEventListenerAbortController.tentative.html

+<!DOCTYPE html>
+<meta charset="utf-8">
+<link rel="author" title="Joey Arhar" href="mailto:jarhar@chromium.org">
+
+<!-- This behavior has not been specified yet. See https://github.com/whatwg/dom/issues/911 -->
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<body>
+
+<script>
+test(t => {
+  const target = new EventTarget();
+  const controller = new AbortController();
+
+  target.addEventListener('testevent', t.step_func(() => {
+    assert_unreached('testevent should have been canceled by AbortController');
+  }), {signal: controller.signal});
+
+  controller.abort();
+  target.dispatchEvent(new Event('testevent'));
+}, 'Tests support for EventController to cancel event listeners in addEventListener.');
+</script>

tools/metrics/histograms/enums.xml

@@ -30235,6 +30235,7 @@ Called by update_use_counter_feature_enum.py.-->
   <int value="3727" label="AdFrameDetected"/>
   <int value="3728" label="MediaStreamTrackGenerator"/>
   <int value="3729" label="MediaStreamTrackProcessor"/>
+  <int value="3730" label="AddEventListenerWithAbortSignal"/>
 </enum>
 
 <enum name="FeaturePolicyAllowlistType">