Blink GC plugin: remove temporary exceptions for the TreeShared/Node hierarchy.

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 917d070b040416ffe1780584510b11a8435ab883..765e32ae8db7fe933d1b6cc7cbd50fa6e42edf02 100644
--- a/tools/clang/blink_gc_plugin/Config.h
+++ b/tools/clang/blink_gc_plugin/Config.h
@@ -111,10 +111,6 @@ class Config {
            IsGCMixinBase(name);
   }
 
-  static bool IsTreeSharedBase(const std::string& name) {
-    return name == "TreeShared";
-  }
-
   static bool IsAnnotated(clang::Decl* decl, const std::string& anno) {
     clang::AnnotateAttr* attr = decl->getAttr<clang::AnnotateAttr>();
     return attr && (attr->getAnnotation() == anno);