blink_gc_plugin: retire overloaded traceImpl detection and handling.

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

Index: tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl_error.cpp
diff --git a/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl_error.cpp b/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl_error.cpp
index 041c565e54d45f6651d4c536d09b88f3cfef50f1..3a7638a397f3761665252a816ad1ed4a4381f3ba 100644
--- a/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl_error.cpp
+++ b/tools/clang/blink_gc_plugin/tests/legacy_naming/traceimpl_error.cpp
@@ -7,22 +7,10 @@
 namespace blink {
 
 void TraceImplExternWithUntracedMember::trace(Visitor* visitor) {
-  traceImpl(visitor);
-}
-
-template <typename VisitorDispatcher>
-inline void TraceImplExternWithUntracedMember::traceImpl(
-    VisitorDispatcher visitor) {
   // Should get a warning as well.
 }
 
 void TraceImplExternWithUntracedBase::trace(Visitor* visitor) {
-  traceImpl(visitor);
-}
-
-template <typename VisitorDispatcher>
-inline void TraceImplExternWithUntracedBase::traceImpl(
-    VisitorDispatcher visitor) {
   // Ditto.
 }