[Trusted Types] JS event tracking for policy creation

Add a new event listener `beforecreatepolicy` to
TrustedTypePolicyFactory::createPolicy which allow
people to track or block the creation process for
Trusted Types.

Bug: 1075601
Change-Id: Ib885e7adc740999ba0e39037b7f4a90af6ff6aef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2260594
Commit-Queue: Yifan Luo <lyf@chromium.org>
Reviewed-by: Daniel Vogelheim <vogelheim@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789409}

third_party/blink/renderer/bindings/idl_in_core.gni

@@ -180,6 +180,7 @@ static_idl_files_in_core = get_path_info(
           "//third_party/blink/renderer/core/events/animation_playback_event_init.idl",
           "//third_party/blink/renderer/core/events/application_cache_error_event.idl",
           "//third_party/blink/renderer/core/events/application_cache_error_event_init.idl",
+          "//third_party/blink/renderer/core/events/before_create_policy_event.idl",
           "//third_party/blink/renderer/core/events/before_unload_event.idl",
           "//third_party/blink/renderer/core/events/clipboard_event.idl",
           "//third_party/blink/renderer/core/events/clipboard_event_init.idl",

third_party/blink/renderer/core/BUILD.gn

@@ -305,6 +305,7 @@ generate_event_interfaces("core_event_interfaces") {
     "events/animation_event.idl",
     "events/animation_playback_event.idl",
     "events/application_cache_error_event.idl",
+    "events/before_create_policy_event.idl",
     "events/before_unload_event.idl",
     "events/clipboard_event.idl",
     "events/composition_event.idl",

third_party/blink/renderer/core/core_idl_files.gni

@@ -146,6 +146,7 @@ core_interface_idl_files_core_only =
                     "events/animation_event.idl",
                     "events/animation_playback_event.idl",
                     "events/application_cache_error_event.idl",
+                    "events/before_create_policy_event.idl",
                     "events/before_unload_event.idl",
                     "events/clipboard_event.idl",
                     "events/composition_event.idl",

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

@@ -235,6 +235,10 @@ bool Event::IsBeforeTextInsertedEvent() const {
   return false;
 }
 
+bool Event::IsBeforeCreatePolicyEvent() const {
+  return false;
+}
+
 bool Event::IsBeforeUnloadEvent() const {
   return false;
 }

third_party/blink/renderer/core/dom/events/event.h

@@ -227,6 +227,7 @@ class CORE_EXPORT Event : public ScriptWrappable {
   virtual bool IsClipboardEvent() const;
   virtual bool IsBeforeTextInsertedEvent() const;
 
+  virtual bool IsBeforeCreatePolicyEvent() const;
   virtual bool IsBeforeUnloadEvent() const;
   virtual bool IsErrorEvent() const;
 

third_party/blink/renderer/core/events/BUILD.gn

@@ -13,6 +13,8 @@ blink_core_sources("events") {
     "animation_playback_event.h",
     "application_cache_error_event.cc",
     "application_cache_error_event.h",
+    "before_create_policy_event.cc",
+    "before_create_policy_event.h",
     "before_print_event.h",
     "before_text_inserted_event.cc",
     "before_text_inserted_event.h",

third_party/blink/renderer/core/events/before_create_policy_event.cc

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "before_create_policy_event.h"
+
+#include "third_party/blink/renderer/core/event_interface_names.h"
+#include "third_party/blink/renderer/core/event_type_names.h"
+
+namespace blink {
+
+BeforeCreatePolicyEvent* BeforeCreatePolicyEvent::Create(
+    const String& policy_name) {
+  return MakeGarbageCollected<BeforeCreatePolicyEvent>(policy_name);
+}
+
+BeforeCreatePolicyEvent::BeforeCreatePolicyEvent(const String& policy_name)
+    : Event(event_type_names::kBeforecreatepolicy,
+            Bubbles::kNo,
+            Cancelable::kYes),
+      policy_name_(policy_name) {}
+
+BeforeCreatePolicyEvent::~BeforeCreatePolicyEvent() = default;
+
+bool BeforeCreatePolicyEvent::IsBeforeCreatePolicyEvent() const {
+  return true;
+}
+
+const AtomicString& BeforeCreatePolicyEvent::InterfaceName() const {
+  return event_interface_names::kBeforeCreatePolicyEvent;
+}
+
+void BeforeCreatePolicyEvent::Trace(Visitor* visitor) const {
+  Event::Trace(visitor);
+}
+
+}  // namespace blink

third_party/blink/renderer/core/events/before_create_policy_event.h

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_EVENTS_BEFORE_CREATE_POLICY_EVENT_H_
+#define THIRD_PARTY_BLINK_RENDERER_CORE_EVENTS_BEFORE_CREATE_POLICY_EVENT_H_
+
+#include "third_party/blink/renderer/core/core_export.h"
+#include "third_party/blink/renderer/core/dom/events/event.h"
+#include "third_party/blink/renderer/platform/wtf/casting.h"
+
+namespace blink {
+
+class CORE_EXPORT BeforeCreatePolicyEvent final : public Event {
+  DEFINE_WRAPPERTYPEINFO();
+
+ public:
+  static BeforeCreatePolicyEvent* Create(const String&);
+  explicit BeforeCreatePolicyEvent(const String&);
+  ~BeforeCreatePolicyEvent() override;
+
+  bool IsBeforeCreatePolicyEvent() const override;
+
+  void setPolicyName(const String& policy_name) { policy_name_ = policy_name; }
+
+  String policyName() const { return policy_name_; }
+
+  const AtomicString& InterfaceName() const override;
+
+  void Trace(Visitor*) const override;
+
+ private:
+  String policy_name_;
+};
+
+template <>
+struct DowncastTraits<BeforeCreatePolicyEvent> {
+  static bool AllowFrom(const Event& event) {
+    return event.IsBeforeCreatePolicyEvent();
+  }
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_EVENTS_BEFORE_CREATE_POLICY_EVENT_H_

third_party/blink/renderer/core/events/before_create_policy_event.idl

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// https://github.com/w3c/webappsec-trusted-types/issues/270#issue-579152412
+
+[RuntimeEnabled=TrustedTypeBeforePolicyCreationEvent, Exposed=Window]
+interface BeforeCreatePolicyEvent : Event {
+    attribute DOMString policyName;
+};
\ No newline at end of file

third_party/blink/renderer/core/events/event_target_names.json5

@@ -25,6 +25,7 @@
     "TextTrack",
     "TextTrackCue",
     "TextTrackList",
+    "TrustedTypePolicyFactory",
     "VideoTrackList",
     "ApplicationCache",
     "MojoInterfaceInterceptor",

third_party/blink/renderer/core/events/event_type_names.json5

@@ -46,6 +46,7 @@
     "backgroundfetchsuccess",
     "beforematch",
     "beforecopy",
+    "beforecreatepolicy",
     "beforecut",
     "beforeinput",
     "beforeinstallprompt",

third_party/blink/renderer/core/trustedtypes/trusted_type_policy_factory.cc

@@ -9,6 +9,9 @@
 #include "third_party/blink/renderer/bindings/core/v8/v8_trusted_html.h"
 #include "third_party/blink/renderer/bindings/core/v8/v8_trusted_script.h"
 #include "third_party/blink/renderer/bindings/core/v8/v8_trusted_script_url.h"
+#include "third_party/blink/renderer/core/dom/document.h"
+#include "third_party/blink/renderer/core/dom/events/event.h"
+#include "third_party/blink/renderer/core/events/before_create_policy_event.h"
 #include "third_party/blink/renderer/core/execution_context/execution_context.h"
 #include "third_party/blink/renderer/core/frame/csp/content_security_policy.h"
 #include "third_party/blink/renderer/core/frame/local_frame.h"
@@ -17,6 +20,7 @@
 #include "third_party/blink/renderer/platform/bindings/exception_state.h"
 #include "third_party/blink/renderer/platform/bindings/v8_dom_wrapper.h"
 #include "third_party/blink/renderer/platform/instrumentation/use_counter.h"
+#include "third_party/blink/renderer/platform/runtime_enabled_features.h"
 #include "third_party/blink/renderer/platform/wtf/text/string_hash.h"
 
 namespace blink {
@@ -25,6 +29,16 @@ TrustedTypePolicy* TrustedTypePolicyFactory::createPolicy(
     const String& policy_name,
     const TrustedTypePolicyOptions* policy_options,
     ExceptionState& exception_state) {
+  if (RuntimeEnabledFeatures::TrustedTypeBeforePolicyCreationEventEnabled()) {
+    DispatchEventResult result =
+        DispatchEvent(*BeforeCreatePolicyEvent::Create(policy_name));
+    if (result != DispatchEventResult::kNotCanceled) {
+      exception_state.ThrowDOMException(
+          DOMExceptionCode::kNotAllowedError,
+          "The policy creation has been canceled.");
+      return nullptr;
+    }
+  }
   if (!GetExecutionContext()) {
     exception_state.ThrowDOMException(DOMExceptionCode::kInvalidStateError,
                                       "The document is detached.");
@@ -308,8 +322,16 @@ void TrustedTypePolicyFactory::CountTrustedTypeAssignmentError() {
   }
 }
 
+const AtomicString& TrustedTypePolicyFactory::InterfaceName() const {
+  return event_target_names::kTrustedTypePolicyFactory;
+}
+
+ExecutionContext* TrustedTypePolicyFactory::GetExecutionContext() const {
+  return ExecutionContextClient::GetExecutionContext();
+}
+
 void TrustedTypePolicyFactory::Trace(Visitor* visitor) const {
-  ScriptWrappable::Trace(visitor);
+  EventTargetWithInlineData::Trace(visitor);
   ExecutionContextClient::Trace(visitor);
   visitor->Trace(empty_html_);
   visitor->Trace(empty_script_);

third_party/blink/renderer/core/trustedtypes/trusted_type_policy_factory.h

@@ -6,6 +6,7 @@
 #define THIRD_PARTY_BLINK_RENDERER_CORE_TRUSTEDTYPES_TRUSTED_TYPE_POLICY_FACTORY_H_
 
 #include "third_party/blink/renderer/core/core_export.h"
+#include "third_party/blink/renderer/core/dom/events/event_target.h"
 #include "third_party/blink/renderer/core/execution_context/execution_context_lifecycle_observer.h"
 #include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
 #include "third_party/blink/renderer/platform/heap/heap_allocator.h"
@@ -22,7 +23,7 @@ class TrustedTypePolicy;
 class TrustedTypePolicyOptions;
 
 class CORE_EXPORT TrustedTypePolicyFactory final
-    : public ScriptWrappable,
+    : public EventTargetWithInlineData,
       public ExecutionContextClient {
   DEFINE_WRAPPERTYPEINFO();
   USING_GARBAGE_COLLECTED_MIXIN(TrustedTypePolicyFactory);
@@ -37,6 +38,8 @@ class CORE_EXPORT TrustedTypePolicyFactory final
 
   TrustedTypePolicy* defaultPolicy() const;
 
+  DEFINE_ATTRIBUTE_EVENT_LISTENER(beforecreatepolicy, kBeforecreatepolicy)
+
   bool isHTML(ScriptState*, const ScriptValue&);
   bool isScript(ScriptState*, const ScriptValue&);
   bool isScriptURL(ScriptState*, const ScriptValue&);
@@ -68,6 +71,8 @@ class CORE_EXPORT TrustedTypePolicyFactory final
   //  relate it to the total number of TT enabled documents.)
   void CountTrustedTypeAssignmentError();
 
+  const AtomicString& InterfaceName() const override;
+  ExecutionContext* GetExecutionContext() const override;
   void Trace(Visitor*) const override;
 
  private:

third_party/blink/renderer/core/trustedtypes/trusted_type_policy_factory.idl

@@ -7,7 +7,7 @@
 [
     Exposed=(Window, Worker),
     RuntimeEnabled=TrustedDOMTypes
-] interface TrustedTypePolicyFactory {
+] interface TrustedTypePolicyFactory : EventTarget {
     [RaisesException] TrustedTypePolicy createPolicy(DOMString policyName, TrustedTypePolicyOptions policyOptions);
     readonly attribute TrustedTypePolicy defaultPolicy;
     // All the policy object names that have been created
@@ -24,4 +24,6 @@
     DOMString? getAttributeType(DOMString tagName, DOMString attribute,
         optional DOMString elementNS, optional DOMString attrNs);
     [CallWith=ScriptState] object? getTypeMapping(optional DOMString ns);
+
+    [RuntimeEnabled=TrustedTypeBeforePolicyCreationEvent] attribute EventHandler onbeforecreatepolicy;
 };

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1840,6 +1840,10 @@
       name: "TrustedDOMTypes",
       status: "stable",
     },
+    {
+      name: "TrustedTypeBeforePolicyCreationEvent",
+      status: "experimental",
+    },
     {
       name: "TrustTokens",
       origin_trial_feature_name: "TrustTokens",

third_party/blink/web_tests/external/wpt/interfaces/trusted-types.tentative.idl

@@ -28,7 +28,7 @@ typedef [StringContext=TrustedScriptURL] USVString ScriptURLString;
 [
   Exposed=(Window, Worker),
   SecureContext
-] interface TrustedTypePolicyFactory {
+] interface TrustedTypePolicyFactory : EventTarget {
     TrustedTypePolicy createPolicy(DOMString policyName, optional TrustedTypePolicyOptions policyOptions = {});
     // All the policy object names that have been created
 };

third_party/blink/web_tests/external/wpt/trusted-types/TrustedTypePolicyFactory-blocking.html

+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="support/helper.sub.js"></script>
+<meta http-equiv="Content-Security-Policy" content="trusted-types *">
+
+<body>
+<script>
+
+  test(t => {
+    event_listener = (e) => {
+      assert_equals(e.policyName, "default");
+      e.preventDefault(); // don't let this policy be created.
+    };
+    trustedTypes.addEventListener('beforecreatepolicy', event_listener, {once:true});
+    assert_throws_dom("NotAllowedError", () => trustedTypes.createPolicy("default", {}));
+  }, 'Block Trusted Type policy creation by event listener.');
+
+  test(t => {
+    let flag = false;
+    event_listener = (e) => {
+      assert_equals(e.policyName, "myPolicy");
+      flag = true;
+    };
+    trustedTypes.addEventListener('beforecreatepolicy', event_listener, {once:true});
+    trustedTypes.createPolicy("myPolicy", {});
+    assert_equals(flag, true);
+  }, 'Trusted Type policy creation.');
+
+  test(t => {
+    event_listener = (e) => {
+      if (e.policyName === "default")
+        e.preventDefault();
+    };
+    trustedTypes.addEventListener('beforecreatepolicy', event_listener, {once:true});
+    assert_throws_dom("NotAllowedError", () => trustedTypes.createPolicy("default", {}));
+    trustedTypes.createPolicy("newPolicy", {});
+  }, 'Block only default Trusted Type policy creation.');
+
+  test(t => {
+    event_listener = (e) => {
+      assert_unreached();
+    };
+    trustedTypes.createPolicy("test", {});
+    trustedTypes.addEventListener('beforecreatepolicy', event_listener, {once:true});
+  }, 'Policy creation called before addEventListener function will not reached the listener.');
+
+</script>
\ No newline at end of file

third_party/blink/web_tests/fast/dom/Window/property-access-on-cached-properties-after-frame-navigated-expected.txt

@@ -116,6 +116,7 @@ PASS window.cached_statusbar.visible is false
 PASS window.cached_styleMedia.type is ''
 PASS window.cached_toolbar.visible is false
 PASS window.cached_trustedTypes.defaultPolicy is null
+PASS window.cached_trustedTypes.onbeforecreatepolicy is null
 PASS window.cached_visualViewport.height is 0
 PASS window.cached_visualViewport.offsetLeft is 0
 PASS window.cached_visualViewport.offsetTop is 0

third_party/blink/web_tests/fast/dom/Window/property-access-on-cached-properties-after-frame-removed-and-gced-expected.txt

@@ -116,6 +116,7 @@ PASS window.cached_statusbar.visible is false
 PASS window.cached_styleMedia.type is ''
 PASS window.cached_toolbar.visible is false
 PASS window.cached_trustedTypes.defaultPolicy is null
+PASS window.cached_trustedTypes.onbeforecreatepolicy is null
 PASS window.cached_visualViewport.height is 0
 PASS window.cached_visualViewport.offsetLeft is 0
 PASS window.cached_visualViewport.offsetTop is 0

third_party/blink/web_tests/fast/dom/Window/property-access-on-cached-properties-after-frame-removed-expected.txt

@@ -116,6 +116,7 @@ PASS window.cached_statusbar.visible is false
 PASS window.cached_styleMedia.type is ''
 PASS window.cached_toolbar.visible is false
 PASS window.cached_trustedTypes.defaultPolicy is null
+PASS window.cached_trustedTypes.onbeforecreatepolicy is null
 PASS window.cached_visualViewport.height is 0
 PASS window.cached_visualViewport.offsetLeft is 0
 PASS window.cached_visualViewport.offsetTop is 0

third_party/blink/web_tests/fast/dom/Window/property-access-on-cached-window-after-frame-navigated-expected.txt

@@ -254,6 +254,7 @@ PASS oldChildWindow.statusbar.visible is newChildWindow.statusbar.visible
 PASS oldChildWindow.styleMedia.type is newChildWindow.styleMedia.type
 PASS oldChildWindow.toolbar.visible is newChildWindow.toolbar.visible
 PASS oldChildWindow.trustedTypes.defaultPolicy is newChildWindow.trustedTypes.defaultPolicy
+PASS oldChildWindow.trustedTypes.onbeforecreatepolicy is newChildWindow.trustedTypes.onbeforecreatepolicy
 PASS oldChildWindow.visualViewport.height is newChildWindow.visualViewport.height
 PASS oldChildWindow.visualViewport.offsetLeft is newChildWindow.visualViewport.offsetLeft
 PASS oldChildWindow.visualViewport.offsetTop is newChildWindow.visualViewport.offsetTop

third_party/blink/web_tests/fast/dom/Window/property-access-on-cached-window-after-frame-removed-and-gced-expected.txt

@@ -195,6 +195,7 @@ PASS childWindow.statusbar.visible is false
 PASS childWindow.styleMedia.type is ''
 PASS childWindow.toolbar.visible is false
 PASS childWindow.trustedTypes.defaultPolicy is null
+PASS childWindow.trustedTypes.onbeforecreatepolicy is null
 PASS childWindow.visualViewport.height is 0
 PASS childWindow.visualViewport.offsetLeft is 0
 PASS childWindow.visualViewport.offsetTop is 0

third_party/blink/web_tests/fast/dom/Window/property-access-on-cached-window-after-frame-removed-expected.txt

@@ -195,6 +195,7 @@ PASS childWindow.statusbar.visible is false
 PASS childWindow.styleMedia.type is ''
 PASS childWindow.toolbar.visible is false
 PASS childWindow.trustedTypes.defaultPolicy is null
+PASS childWindow.trustedTypes.onbeforecreatepolicy is null
 PASS childWindow.visualViewport.height is 0
 PASS childWindow.visualViewport.offsetLeft is 0
 PASS childWindow.visualViewport.offsetTop is 0

third_party/blink/web_tests/http/tests/serviceworker/webexposed/global-interface-listing-service-worker-expected.txt

@@ -1495,11 +1495,12 @@ interface TransformStream
     getter readable
     getter writable
     method constructor
-interface TrustedTypePolicyFactory
+interface TrustedTypePolicyFactory : EventTarget
     attribute @@toStringTag
     getter defaultPolicy
     getter emptyHTML
     getter emptyScript
+    getter onbeforecreatepolicy
     method constructor
     method createPolicy
     method getAttributeType
@@ -1508,6 +1509,7 @@ interface TrustedTypePolicyFactory
     method isHTML
     method isScript
     method isScriptURL
+    setter onbeforecreatepolicy
 interface URL
     attribute @@toStringTag
     getter hash

third_party/blink/web_tests/virtual/stable/http/tests/serviceworker/webexposed/global-interface-listing-service-worker-expected.txt

@@ -1233,7 +1233,7 @@ interface TransformStream
     getter readable
     getter writable
     method constructor
-interface TrustedTypePolicyFactory
+interface TrustedTypePolicyFactory : EventTarget
     attribute @@toStringTag
     getter defaultPolicy
     getter emptyHTML

third_party/blink/web_tests/virtual/stable/webexposed/global-interface-listing-dedicated-worker-expected.txt

@@ -1141,7 +1141,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter readable
 [Worker]     getter writable
 [Worker]     method constructor
-[Worker] interface TrustedTypePolicyFactory
+[Worker] interface TrustedTypePolicyFactory : EventTarget
 [Worker]     attribute @@toStringTag
 [Worker]     getter defaultPolicy
 [Worker]     getter emptyHTML

third_party/blink/web_tests/virtual/stable/webexposed/global-interface-listing-expected.txt

@@ -7322,7 +7322,7 @@ interface TrustedTypePolicy
     method createHTML
     method createScript
     method createScriptURL
-interface TrustedTypePolicyFactory
+interface TrustedTypePolicyFactory : EventTarget
     attribute @@toStringTag
     getter defaultPolicy
     getter emptyHTML

third_party/blink/web_tests/virtual/stable/webexposed/global-interface-listing-shared-worker-expected.txt

@@ -1141,7 +1141,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter readable
 [Worker]     getter writable
 [Worker]     method constructor
-[Worker] interface TrustedTypePolicyFactory
+[Worker] interface TrustedTypePolicyFactory : EventTarget
 [Worker]     attribute @@toStringTag
 [Worker]     getter defaultPolicy
 [Worker]     getter emptyHTML

third_party/blink/web_tests/webexposed/global-interface-listing-dedicated-worker-expected.txt

@@ -1473,11 +1473,12 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter readable
 [Worker]     getter writable
 [Worker]     method constructor
-[Worker] interface TrustedTypePolicyFactory
+[Worker] interface TrustedTypePolicyFactory : EventTarget
 [Worker]     attribute @@toStringTag
 [Worker]     getter defaultPolicy
 [Worker]     getter emptyHTML
 [Worker]     getter emptyScript
+[Worker]     getter onbeforecreatepolicy
 [Worker]     method constructor
 [Worker]     method createPolicy
 [Worker]     method getAttributeType
@@ -1486,6 +1487,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     method isHTML
 [Worker]     method isScript
 [Worker]     method isScriptURL
+[Worker]     setter onbeforecreatepolicy
 [Worker] interface URL
 [Worker]     static method createObjectURL
 [Worker]     static method revokeObjectURL

third_party/blink/web_tests/webexposed/global-interface-listing-expected.txt

@@ -487,6 +487,11 @@ interface BatteryManager : EventTarget
     setter onchargingtimechange
     setter ondischargingtimechange
     setter onlevelchange
+interface BeforeCreatePolicyEvent : Event
+    attribute @@toStringTag
+    getter policyName
+    method constructor
+    setter policyName
 interface BeforeInstallPromptEvent : Event
     attribute @@toStringTag
     getter platforms
@@ -8522,11 +8527,12 @@ interface TrustedTypePolicy
     method createHTML
     method createScript
     method createScriptURL
-interface TrustedTypePolicyFactory
+interface TrustedTypePolicyFactory : EventTarget
     attribute @@toStringTag
     getter defaultPolicy
     getter emptyHTML
     getter emptyScript
+    getter onbeforecreatepolicy
     method constructor
     method createPolicy
     method getAttributeType
@@ -8535,6 +8541,7 @@ interface TrustedTypePolicyFactory
     method isHTML
     method isScript
     method isScriptURL
+    setter onbeforecreatepolicy
 interface UIEvent : Event
     attribute @@toStringTag
     getter detail

third_party/blink/web_tests/webexposed/global-interface-listing-shared-worker-expected.txt

@@ -1372,11 +1372,12 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter readable
 [Worker]     getter writable
 [Worker]     method constructor
-[Worker] interface TrustedTypePolicyFactory
+[Worker] interface TrustedTypePolicyFactory : EventTarget
 [Worker]     attribute @@toStringTag
 [Worker]     getter defaultPolicy
 [Worker]     getter emptyHTML
 [Worker]     getter emptyScript
+[Worker]     getter onbeforecreatepolicy
 [Worker]     method constructor
 [Worker]     method createPolicy
 [Worker]     method getAttributeType
@@ -1385,6 +1386,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     method isHTML
 [Worker]     method isScript
 [Worker]     method isScriptURL
+[Worker]     setter onbeforecreatepolicy
 [Worker] interface URL
 [Worker]     static method createObjectURL
 [Worker]     static method revokeObjectURL