Oilpan: Remove GC_INFO_{DEFINE,DECLARE} macros

Source/heap/Visitor.h

Index: Source/heap/Visitor.h
diff --git a/Source/heap/Visitor.h b/Source/heap/Visitor.h
index 80623bf29531b79daa213ccdecb17877dff4bd6d..c98b13e08ae848dbad71e3214a11fbd3c463cf9c 100644
--- a/Source/heap/Visitor.h
+++ b/Source/heap/Visitor.h
@@ -134,31 +134,9 @@ struct FinalizerTrait {
     static void finalize(void* obj) { FinalizerTraitImpl<T, nonTrivialFinalizer>::finalize(obj); }
 };
 
-// Macros to declare and define GCInfo structures for objects
-// allocated in the Blink garbage-collected heap.
-#define DECLARE_GC_INFO                                                       \
-public:                                                                       \
-    static const GCInfo s_gcInfo;                                             \
-    template<typename Any> friend struct FinalizerTrait;                      \
-private:                                                                      \
-
-#define DEFINE_GC_INFO(Type)                                                  \
-const GCInfo Type::s_gcInfo = {                                               \
-    #Type,                                                                    \
-    TraceTrait<Type>::trace,                                                  \
-    FinalizerTrait<Type>::finalize,                                           \
-    FinalizerTrait<Type>::nonTrivialFinalizer,                                \
-};                                                                            \
-
 // Trait to get the GCInfo structure for types that have their
 // instances allocated in the Blink garbage-collected heap.
-template<typename T>
-struct GCInfoTrait {
-    static const GCInfo* get()
-    {
-        return &T::s_gcInfo;
-    }
-};
+template<typename T> struct GCInfoTrait;
 
 template<typename T>
 const char* getTypeMarker()
@@ -545,6 +523,29 @@ template<typename T> bool ObjectAliveTrait<Member<T> >::isAlive(Visitor* visitor
     return visitor->isMarked(obj.get());
 }
 
+template<typename T>
+struct GCInfoAtBase {
+    static const GCInfo* get()
+    {
+        static char pseudoTypeMarker = 'a';
+        static const GCInfo gcInfo = {
+            &pseudoTypeMarker,
+            TraceTrait<T>::trace,
+            FinalizerTrait<T>::finalize,
+            FinalizerTrait<T>::nonTrivialFinalizer,
+        };
+        return &gcInfo;
+    }
+};
+
+template<typename T>
+struct GCInfoTrait {
+    static const GCInfo* get()
+    {
+        return GCInfoAtBase<typename T::GarbageCollectedBase>::get();
+    }
+};
+
 }
 
 #endif