Unify phantom and internal fields weak handle callbacks

src/global-handles.h

Index: src/global-handles.h
diff --git a/src/global-handles.h b/src/global-handles.h
index b3756d0e62035f41d980f5efbe17538414ec2eb8..fe9ed5a2585afccd400b3f94c1efd3e504736527 100644
--- a/src/global-handles.h
+++ b/src/global-handles.h
@@ -98,9 +98,15 @@ struct ObjectGroupRetainerInfo {
 
 
 enum WeaknessType {
-  NORMAL_WEAK,          // Embedder gets a handle to the dying object.
-  PHANTOM_WEAK,         // Embedder gets the parameter they passed in earlier.
-  INTERNAL_FIELDS_WEAK  // Embedder gets 2 internal fields from dying object.
+  NORMAL_WEAK,  // Embedder gets a handle to the dying object.
+  // In the following cases, the embedder gets the parameter they passed in
+  // earlier, and the 0, 1 or 2 first internal fields. Note that the internal
+  // fields must contain aligned non-V8 pointers.  Getting pointers to V8
+  // objects through this interface would be GC unsafe so in that case the
+  // embedder gets a null pointer instead.
+  PHANTOM_WEAK_0_INTERNAL_FIELDS,
+  PHANTOM_WEAK_1_INTERNAL_FIELDS,
+  PHANTOM_WEAK_2_INTERNAL_FIELDS
 };
 
 
@@ -139,14 +145,9 @@ class GlobalHandles {
 
   // It would be nice to template this one, but it's really hard to get
   // the template instantiator to work right if you do.
-  static void MakePhantom(Object** location, void* parameter,
-                          PhantomCallbackData<void>::Callback weak_callback);
-
   static void MakePhantom(
-      Object** location,
-      v8::InternalFieldsCallbackData<void, void>::Callback weak_callback,
-      int16_t internal_field_index1,
-      int16_t internal_field_index2 = v8::Object::kNoInternalFieldIndex);
+      Object** location, void* parameter, int number_of_internal_fields,
+      PhantomCallbackData<void, void, void>::Callback weak_callback);
 
   void RecordStats(HeapStats* stats);
 
@@ -302,7 +303,6 @@ class GlobalHandles {
   class NodeBlock;
   class NodeIterator;
   class PendingPhantomCallback;
-  class PendingInternalFieldsCallback;
 
   Isolate* isolate_;
 
@@ -336,7 +336,6 @@ class GlobalHandles {
   List<ObjectGroupConnection> implicit_ref_connections_;
 
   List<PendingPhantomCallback> pending_phantom_callbacks_;
-  List<PendingInternalFieldsCallback> pending_internal_fields_callbacks_;
 
   friend class Isolate;
 
@@ -346,7 +345,7 @@ class GlobalHandles {
 
 class GlobalHandles::PendingPhantomCallback {
  public:
-  typedef PhantomCallbackData<void> Data;
+  typedef PhantomCallbackData<void, void, void> Data;
   PendingPhantomCallback(Node* node, Data data, Data::Callback callback)
       : node_(node), data_(data), callback_(callback) {}
 
@@ -361,20 +360,6 @@ class GlobalHandles::PendingPhantomCallback {
 };
 
 
-class GlobalHandles::PendingInternalFieldsCallback {
- public:
-  typedef InternalFieldsCallbackData<void, void> Data;
-  PendingInternalFieldsCallback(Data data, Data::Callback callback)
-      : data_(data), callback_(callback) {}
-
-  void invoke() { callback_(data_); }
-
- private:
-  Data data_;
-  Data::Callback callback_;
-};
-
-
 class EternalHandles {
  public:
   enum SingletonHandle {