Add RETURN_NULL_ERROR to new apis

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, 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.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "lib/stacktrace.h"
@@ skipping 5870 matching lines @@
   }
   lib.set_native_entry_resolver(resolver);
   lib.set_native_entry_symbol_resolver(symbol);
   return Api::Success();
 }
 
 
 DART_EXPORT Dart_Handle
 Dart_GetNativeResolver(Dart_Handle library,
                        Dart_NativeEntryResolver* resolver) {
+  if (resolver == NULL) {
+    RETURN_NULL_ERROR(resolver);
+  }
   *resolver = NULL;
   DARTSCOPE(Thread::Current());
   const Library& lib = Api::UnwrapLibraryHandle(Z, library);
   if (lib.IsNull()) {
     RETURN_TYPE_ERROR(Z, library, Library);
   }
   *resolver = lib.native_entry_resolver();
   return Api::Success();
 }
 
 
 DART_EXPORT Dart_Handle Dart_GetNativeSymbol(Dart_Handle library,
                                              Dart_NativeEntrySymbol* resolver) {
+  if (resolver == NULL) {
+    RETURN_NULL_ERROR(resolver);
+  }
   *resolver = NULL;
   DARTSCOPE(Thread::Current());
   const Library& lib = Api::UnwrapLibraryHandle(Z, library);
   if (lib.IsNull()) {
     RETURN_TYPE_ERROR(Z, library, Library);
   }
   *resolver = lib.native_entry_symbol_resolver();
   return Api::Success();
 }
 
@@ skipping 730 matching lines @@
 
 DART_EXPORT bool Dart_IsPrecompiledRuntime() {
 #if defined(DART_PRECOMPILED_RUNTIME)
   return true;
 #else
   return false;
 #endif
 }
 
 }  // namespace dart