blink_gc_plugin: retire overloaded traceImpl detection and handling.

tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl_overloaded_error.h

Index: tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl_overloaded_error.h
diff --git a/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl_overloaded_error.h b/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl_overloaded_error.h
index 7d7a03837c6b268512f4d9e6aa2df5f85500df17..8d6e950459978d3b84da161d3d18963920d29e6f 100644
--- a/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl_overloaded_error.h
+++ b/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl_overloaded_error.h
@@ -12,19 +12,11 @@ namespace blink {
 class X : public GarbageCollected<X> {
  public:
   void trace(Visitor*) {}
-  void trace(InlinedGlobalMarkingVisitor) {}
 };
 
 class InlinedBase : public GarbageCollected<InlinedBase> {
  public:
-  virtual void trace(Visitor* visitor) { traceImpl(visitor); }
-  virtual void trace(InlinedGlobalMarkingVisitor visitor) {
-    traceImpl(visitor);
-  }
-
- private:
-  template <typename VisitorDispatcher>
-  void traceImpl(VisitorDispatcher visitor) {
+  virtual void trace(Visitor* visitor) {
     // Missing visitor->trace(x_base_).
   }
 
@@ -33,14 +25,7 @@ class InlinedBase : public GarbageCollected<InlinedBase> {
 
 class InlinedDerived : public InlinedBase {
  public:
-  void trace(Visitor* visitor) override { traceImpl(visitor); }
-  void trace(InlinedGlobalMarkingVisitor visitor) override {
-    traceImpl(visitor);
-  }
-
- private:
-  template <typename VisitorDispatcher>
-  void traceImpl(VisitorDispatcher visitor) {
+  void trace(Visitor* visitor) override {
     // Missing visitor->trace(x_derived_) and InlinedBase::trace(visitor).
   }
 
@@ -50,24 +35,16 @@ class InlinedDerived : public InlinedBase {
 class ExternBase : public GarbageCollected<ExternBase> {
  public:
   virtual void trace(Visitor*);
-  virtual void trace(InlinedGlobalMarkingVisitor);
 
  private:
-  template <typename VisitorDispatcher>
-  void traceImpl(VisitorDispatcher);
-
   Member<X> x_base_;
 };
 
 class ExternDerived : public ExternBase {
  public:
   void trace(Visitor*) override;
-  void trace(InlinedGlobalMarkingVisitor) override;
 
  private:
-  template <typename VisitorDispatcher>
-  void traceImpl(VisitorDispatcher);
-
   Member<X> x_derived_;
 };