Remove RefCountedGarbageCollected<> GC plugin handling.

tools/clang/blink_gc_plugin/Config.h

Index: tools/clang/blink_gc_plugin/Config.h
diff --git a/tools/clang/blink_gc_plugin/Config.h b/tools/clang/blink_gc_plugin/Config.h
index 7ca8ea4c0f176fce6a46ea9eccc2005c49b3826b..8d331e5581e13e0fdef6e494ae5bc6c7c900dc5a 100644
--- a/tools/clang/blink_gc_plugin/Config.h
+++ b/tools/clang/blink_gc_plugin/Config.h
@@ -133,14 +133,7 @@ class Config {
   }
 
   static bool IsGCFinalizedBase(const std::string& name) {
-    return name == "GarbageCollectedFinalized" ||
-           name == "RefCountedGarbageCollected" ||
-           name == "ThreadSafeRefCountedGarbageCollected";
-  }
-
-  static bool IsGCRefCountedBase(const std::string& name) {
-    return name == "RefCountedGarbageCollected" ||
-           name == "ThreadSafeRefCountedGarbageCollected";
+    return name == "GarbageCollectedFinalized";
   }
 
   static bool IsGCBase(const std::string& name) {