Revert "Remove NullPointerException."

runtime/lib/regexp.cc

 // Copyright (c) 2012, 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 "platform/assert.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 
 #include "lib/regexp_jsc.h"
 
 namespace dart {
 
+static void CheckAndThrowExceptionIfNull(const Instance& obj) {
+  if (obj.IsNull()) {
+    GrowableArray<const Object*> args;
+    Exceptions::ThrowByType(Exceptions::kNullPointer, args);
+  }
+}
+
 
 DEFINE_NATIVE_ENTRY(JSSyntaxRegExp_factory, 4) {
   ASSERT(AbstractTypeArguments::CheckedHandle(
       arguments->NativeArgAt(0)).IsNull());
+  const Instance& arg1 = Instance::CheckedHandle(arguments->NativeArgAt(1));
+  CheckAndThrowExceptionIfNull(arg1);
   GET_NATIVE_ARGUMENT(String, pattern, arguments->NativeArgAt(1));
   GET_NATIVE_ARGUMENT(Instance, handle_multi_line, arguments->NativeArgAt(2));
   GET_NATIVE_ARGUMENT(Instance, handle_ignore_case, arguments->NativeArgAt(3));
   bool ignore_case = handle_ignore_case.raw() == Bool::True();
   bool multi_line = handle_multi_line.raw() == Bool::True();
   return Jscre::Compile(pattern, multi_line, ignore_case);
 }
 
 
 DEFINE_NATIVE_ENTRY(JSSyntaxRegExp_getPattern, 1) {
@@ skipping 30 matching lines @@
   args.Add(&pattern);
   args.Add(&errmsg);
   Exceptions::ThrowByType(Exceptions::kIllegalJSRegExp, args);
   return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(JSSyntaxRegExp_ExecuteMatch, 3) {
   const JSRegExp& regexp = JSRegExp::CheckedHandle(arguments->NativeArgAt(0));
   ASSERT(!regexp.IsNull());
+  const Instance& arg1 = Instance::CheckedHandle(arguments->NativeArgAt(1));
+  CheckAndThrowExceptionIfNull(arg1);
   GET_NATIVE_ARGUMENT(String, str, arguments->NativeArgAt(1));
   GET_NATIVE_ARGUMENT(Smi, start_index, arguments->NativeArgAt(2));
   return Jscre::Execute(regexp, str, start_index.Value());
 }
 
 }  // namespace dart