VM: [Kernel] Revert changes to the native ports that introduced peers.

runtime/vm/native_message_handler.h

Index: runtime/vm/native_message_handler.h
diff --git a/runtime/vm/native_message_handler.h b/runtime/vm/native_message_handler.h
index 270064e125eac04426948df19b32ea180ba5690c..713366261f687e261815fe45523dd54153fa537e 100644
--- a/runtime/vm/native_message_handler.h
+++ b/runtime/vm/native_message_handler.h
@@ -15,14 +15,11 @@ namespace dart {
 // native C handlers.
 class NativeMessageHandler : public MessageHandler {
  public:
-  NativeMessageHandler(const char* name,
-                       Dart_NativeMessageHandler func,
-                       void* peer);
+  NativeMessageHandler(const char* name, Dart_NativeMessageHandler func);
   ~NativeMessageHandler();
 
   const char* name() const { return name_; }
   Dart_NativeMessageHandler func() const { return func_; }
-  void* peer() const { return peer_; }
 
   MessageStatus HandleMessage(Message* message);
 
@@ -37,7 +34,6 @@ class NativeMessageHandler : public MessageHandler {
  private:
   char* name_;
   Dart_NativeMessageHandler func_;
-  void* peer_;
 };
 
 }  // namespace dart