Remove unnecessary casts from TraceWrapperV8Reference tracing

Remove unnecessary casts from TraceWrapperV8Reference tracing in preparation for https://chromium-review.googlesource.com/c/chromium/src/+/1356442 because blink_gc_plugin will not be able to recognize cast TraceWrapperV8References as traced.

Bug: 910023
Change-Id: Icc68c8eac74d5a7c320e6fd575cceba71951c57a
Reviewed-on: https://chromium-review.googlesource.com/c/1358318
Commit-Queue: Keishi Hattori <keishi@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613084}

third_party/blink/renderer/bindings/core/v8/script_wrappable_marking_visitor_test.cc

@@ -233,9 +233,7 @@ class HandleContainer
   HandleContainer() = default;
   virtual ~HandleContainer() = default;
 
-  void Trace(blink::Visitor* visitor) {
-    visitor->Trace(handle_.Cast<v8::Value>());
-  }
+  void Trace(blink::Visitor* visitor) { visitor->Trace(handle_); }
 
   void SetValue(v8::Isolate* isolate, v8::Local<v8::String> string) {
     handle_.Set(isolate, string);

third_party/blink/renderer/core/layout/custom/css_layout_definition.cc

@@ -328,9 +328,9 @@ void CSSLayoutDefinition::Instance::Trace(blink::Visitor* visitor) {
 }
 
 void CSSLayoutDefinition::Trace(Visitor* visitor) {
-  visitor->Trace(constructor_.Cast<v8::Value>());
-  visitor->Trace(intrinsic_sizes_.Cast<v8::Value>());
-  visitor->Trace(layout_.Cast<v8::Value>());
+  visitor->Trace(constructor_);
+  visitor->Trace(intrinsic_sizes_);
+  visitor->Trace(layout_);
   visitor->Trace(script_state_);
 }
 

third_party/blink/renderer/core/script/module_script.h

@@ -93,6 +93,9 @@ class CORE_EXPORT ModuleScript final : public Script, public NameClient {
   Member<Modulator> settings_object_;
 
   // https://html.spec.whatwg.org/multipage/webappapis.html#concept-script-record
+  // TODO(keishi): Visitor only defines a trace method for v8::Value so this
+  // needs to be cast.
+  GC_PLUGIN_IGNORE("757708")
   TraceWrapperV8Reference<v8::Module> record_;
 
   // https://html.spec.whatwg.org/multipage/webappapis.html#concept-script-parse-error

third_party/blink/renderer/core/workers/experimental/task_worklet_global_scope.cc

@@ -27,8 +27,8 @@ class TaskDefinition final : public GarbageCollectedFinalized<TaskDefinition> {
   }
 
   void Trace(blink::Visitor* visitor) {
-    visitor->Trace(instance_.Cast<v8::Value>());
-    visitor->Trace(process_.Cast<v8::Value>());
+    visitor->Trace(instance_);
+    visitor->Trace(process_);
   }
 
  private:

third_party/blink/renderer/modules/animationworklet/animator_definition.cc

@@ -20,8 +20,8 @@ AnimatorDefinition::AnimatorDefinition(v8::Isolate* isolate,
 AnimatorDefinition::~AnimatorDefinition() = default;
 
 void AnimatorDefinition::Trace(Visitor* visitor) {
-  visitor->Trace(constructor_.Cast<v8::Value>());
-  visitor->Trace(animate_.Cast<v8::Value>());
+  visitor->Trace(constructor_);
+  visitor->Trace(animate_);
 }
 
 v8::Local<v8::Function> AnimatorDefinition::ConstructorLocal(

third_party/blink/renderer/modules/csspaint/css_paint_definition.cc

@@ -154,8 +154,8 @@ void CSSPaintDefinition::MaybeCreatePaintInstance() {
 }
 
 void CSSPaintDefinition::Trace(Visitor* visitor) {
-  visitor->Trace(constructor_.Cast<v8::Value>());
-  visitor->Trace(paint_.Cast<v8::Value>());
+  visitor->Trace(constructor_);
+  visitor->Trace(paint_);
   visitor->Trace(instance_);
   visitor->Trace(context_settings_);
   visitor->Trace(script_state_);

third_party/blink/renderer/modules/webaudio/audio_worklet_processor_definition.h

@@ -52,8 +52,8 @@ class MODULES_EXPORT AudioWorkletProcessorDefinition final
   void MarkAsSynchronized() { is_synchronized_ = true; }
 
   void Trace(blink::Visitor* visitor) {
-    visitor->Trace(constructor_.Cast<v8::Value>());
-    visitor->Trace(process_.Cast<v8::Value>());
+    visitor->Trace(constructor_);
+    visitor->Trace(process_);
     visitor->Trace(audio_param_descriptors_);
   };
   const char* NameInHeapSnapshot() const override {