blink_gc_plugin: retire overloaded traceImpl detection and handling.

tools/clang/blink_gc_plugin/tests/traceimpl_overloaded.h

Index: tools/clang/blink_gc_plugin/tests/traceimpl_overloaded.h
diff --git a/tools/clang/blink_gc_plugin/tests/traceimpl_overloaded.h b/tools/clang/blink_gc_plugin/tests/traceimpl_overloaded.h
index 63ba65aa6312bedce834993b5010b64d6e8cf35b..73ef3798094ceca93b49e6e8ed8d8f548eaddc98 100644
--- a/tools/clang/blink_gc_plugin/tests/traceimpl_overloaded.h
+++ b/tools/clang/blink_gc_plugin/tests/traceimpl_overloaded.h
@@ -12,33 +12,19 @@ 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);
-  }
+  virtual void Trace(Visitor* visitor) { visitor->Trace(x_base_); }
 
  private:
-  template <typename VisitorDispatcher>
-  void TraceImpl(VisitorDispatcher visitor) { visitor->Trace(x_base_); }
-
   Member<X> x_base_;
 };
 
 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 {
     visitor->Trace(x_derived_);
     InlinedBase::Trace(visitor);
   }
@@ -49,24 +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_;
 };