[API] Remove deprecated WeakCallbackData and related functions.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 5115a4e49f68e4a8e14b81507de3591ddd027f43..37c8c580fc50acbb1ecf895c9ed07a4c2a90b443 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -683,11 +683,6 @@ void V8::RegisterExternallyReferencedObject(i::Object** object,
   isolate->heap()->RegisterExternallyReferencedObject(object);
 }
 
-void V8::MakeWeak(i::Object** object, void* parameter,
-                  WeakCallback weak_callback) {
-  i::GlobalHandles::MakeWeak(object, parameter, weak_callback);
-}
-
 
 void V8::MakeWeak(i::Object** object, void* parameter,
                   int internal_field_index1, int internal_field_index2,