blink_gc_plugin: retire overloaded traceImpl detection and handling.

tools/clang/blink_gc_plugin/tests/traceimpl_overloaded_error.cpp

Index: tools/clang/blink_gc_plugin/tests/traceimpl_overloaded_error.cpp
diff --git a/tools/clang/blink_gc_plugin/tests/traceimpl_overloaded_error.cpp b/tools/clang/blink_gc_plugin/tests/traceimpl_overloaded_error.cpp
index 80d0f65bc50f89efdae1d3b4e3a36a04a3a23ec6..d0d18e5cbfb20466921ebd6093e8be9eb1731319 100644
--- a/tools/clang/blink_gc_plugin/tests/traceimpl_overloaded_error.cpp
+++ b/tools/clang/blink_gc_plugin/tests/traceimpl_overloaded_error.cpp
@@ -7,28 +7,10 @@
 namespace blink {
 
 void ExternBase::Trace(Visitor* visitor) {
-  TraceImpl(visitor);
-}
-
-void ExternBase::Trace(InlinedGlobalMarkingVisitor visitor) {
-  TraceImpl(visitor);
-}
-
-template <typename VisitorDispatcher>
-inline void ExternBase::TraceImpl(VisitorDispatcher visitor) {
   // Missing visitor->Trace(x_base_).
 }
 
 void ExternDerived::Trace(Visitor* visitor) {
-  TraceImpl(visitor);
-}
-
-void ExternDerived::Trace(InlinedGlobalMarkingVisitor visitor) {
-  TraceImpl(visitor);
-}
-
-template <typename VisitorDispatcher>
-inline void ExternDerived::TraceImpl(VisitorDispatcher visitor) {
   // Missing visitor->Trace(x_derived_) and ExternBase::Trace(visitor).
 }