Rename GET_NATIVE_ARGUMENT macro to GET_NON_NULL_NATIVE_ARGUMENT.

runtime/vm/native_entry.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_NATIVE_ENTRY_H_
 #define VM_NATIVE_ENTRY_H_
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
@@ skipping 33 matching lines @@
       arguments->SetReturnUnsafe(                                              \
           DN_Helper##name(arguments->isolate(), arguments));                   \
       if (FLAG_deoptimize_alot) DeoptimizeAll();                               \
     }                                                                          \
     VERIFY_ON_TRANSITION;                                                      \
   }                                                                            \
   static RawObject* DN_Helper##name(Isolate* isolate,                          \
                                     NativeArguments* arguments)
 
 
-// Natives should throw an exception if an illegal argument is passed.
+// Natives should throw an exception if an illegal argument or null is passed.
 // type name = value.
-#define GET_NATIVE_ARGUMENT(type, name, value)                                 \
+#define GET_NON_NULL_NATIVE_ARGUMENT(type, name, value)                        \
   const Instance& __##name##_instance__ =                                      \
       Instance::CheckedHandle(isolate, value);                                 \
   if (!__##name##_instance__.Is##type()) {                                     \
     GrowableArray<const Object*> __args__;                                     \
     __args__.Add(&__##name##_instance__);                                      \
     Exceptions::ThrowByType(Exceptions::kArgument, __args__);                  \
   }                                                                            \
   const type& name = type::Cast(__##name##_instance__);
 
 
+// Natives should throw an exception if an illegal argument is passed.
+// type name = value.
+#define GET_NATIVE_ARGUMENT(type, name, value)                                 \
+  const Instance& __##name##_instance__ =                                      \
+      Instance::CheckedHandle(isolate, value);                                 \
+  type& name = type::Handle(isolate);                                          \
+  if (!__##name##_instance__.IsNull()) {                                       \
+    if (!__##name##_instance__.Is##type()) {                                   \
+      GrowableArray<const Object*> __args__;                                   \
+      __args__.Add(&__##name##_instance__);                                    \
+      Exceptions::ThrowByType(Exceptions::kArgument, __args__);                \
+    }                                                                          \
+  }                                                                            \
+  name ^= value;
+
 
 // Helper class for resolving and handling native functions.
 class NativeEntry : public AllStatic {
  public:
   // Resolve specified dart native function to the actual native entrypoint.
   static NativeFunction ResolveNative(const Class& cls,
                                       const String& function_name,
                                       int number_of_arguments);
 };
 
 }  // namespace dart
 
 #endif  // VM_NATIVE_ENTRY_H_