Copy irregexp related code from V8.

runtime/vm/regexp_assembler.cc

 // Copyright (c) 2014, 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/regexp_assembler.h"
+
+// SNIP
 
 namespace dart {
 
-DEFINE_NATIVE_ENTRY(ClassID_getID, 1) {
-  const Instance& instance =
-      Instance::CheckedHandle(isolate, arguments->NativeArgAt(0));
-  return Smi::New(instance.GetClassId());
+RegExpMacroAssembler::RegExpMacroAssembler(Zone* zone)
+  : slow_safe_compiler_(false),
+    global_mode_(NOT_GLOBAL),
+    zone_(zone) {
 }
 
+
+RegExpMacroAssembler::~RegExpMacroAssembler() {
+}
+
+// SNIP
+
 }  // namespace dart