- Add following additional methods to the API to make returning values

runtime/vm/native_arguments.h

Index: runtime/vm/native_arguments.h
===================================================================
--- runtime/vm/native_arguments.h	(revision 25667)
+++ runtime/vm/native_arguments.h	(working copy)
@@ -47,9 +47,7 @@
 
 #endif
 
-void SetReturnValueHelper(Dart_NativeArguments, Dart_Handle);
 
-
 // Class NativeArguments is used to access arguments passed in from
 // generated dart code to a runtime function or a dart library native
 // function. It is also used to set the return value if any at the slot
@@ -158,9 +156,9 @@
   class ArgcBits : public BitField<int, kArgcBit, kArgcSize> {};
   class InstanceFunctionBit : public BitField<bool, kInstanceFunctionBit, 1> {};
   class ClosureFunctionBit : public BitField<bool, kClosureFunctionBit, 1> {};
+  friend class Api;
   friend class BootstrapNatives;
   friend class Simulator;
-  friend void SetReturnValueHelper(Dart_NativeArguments, Dart_Handle);
 
   // Since this function is passed a RawObject directly, we need to be
   // exceedingly careful when we use it.  If there are any other side