blink_gc_plugin: retire overloaded traceImpl detection and handling.

tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl.cpp

Index: tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl.cpp
diff --git a/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl.cpp b/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl.cpp
index c8849ccf780b8da177754a5f46fac0ebdbd6cdba..a5f3a7a4b2080139a860e95c873e4016f894e35f 100644
--- a/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl.cpp
+++ b/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl.cpp
@@ -7,20 +7,10 @@
 namespace blink {
 
 void TraceImplExtern::trace(Visitor* visitor) {
-  traceImpl(visitor);
-}
-
-template <typename VisitorDispatcher>
-inline void TraceImplExtern::traceImpl(VisitorDispatcher visitor) {
   visitor->trace(x_);
 }
 
 void TraceImplBaseExtern::trace(Visitor* visitor) {
-  traceImpl(visitor);
-}
-
-template <typename VisitorDispatcher>
-inline void TraceImplBaseExtern::traceImpl(VisitorDispatcher visitor) {
   visitor->trace(x_);
   Base::trace(visitor);
 }