Use wrapper tracing for worklets.

third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.cpp

Index: third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.cpp
diff --git a/third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.cpp b/third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.cpp
index 253e21493dc82ae0687383daaf38fe8338d4c2fa..d82cd5f58b99626e23ab89136c6ea2831143aa9c 100644
--- a/third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.cpp
+++ b/third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.cpp
@@ -57,10 +57,6 @@ void PaintWorkletGlobalScope::Dispose() {
   MainThreadDebugger::Instance()->ContextWillBeDestroyed(
       ScriptController()->GetScriptState());
 
-  // Explicitly clear the paint defininitions to break a reference cycle
-  // between them and this global scope.
-  paint_definitions_.clear();
-
   pending_generator_registry_ = nullptr;
   WorkletGlobalScope::Dispose();
 }
@@ -198,7 +194,8 @@ void PaintWorkletGlobalScope::registerPaint(const String& name,
       ScriptController()->GetScriptState(), constructor, paint,
       native_invalidation_properties, custom_invalidation_properties,
       input_argument_types, has_alpha);
-  paint_definitions_.Set(name, definition);
+  paint_definitions_.Set(
+      name, TraceWrapperMember<CSSPaintDefinition>(this, definition));
   pending_generator_registry_->SetDefinition(name, definition);
 }
 
@@ -213,4 +210,10 @@ DEFINE_TRACE(PaintWorkletGlobalScope) {
   MainThreadWorkletGlobalScope::Trace(visitor);
 }
 
+DEFINE_TRACE_WRAPPERS(PaintWorkletGlobalScope) {
+  for (auto definition : paint_definitions_)
+    visitor->TraceWrappers(definition.value);
+  MainThreadWorkletGlobalScope::TraceWrappers(visitor);
+}
+
 }  // namespace blink