[regexp] Implement regexp groups as wrapper.

src/regexp/regexp-ast.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ostreams.h"
 #include "src/regexp/regexp-ast.h"
 
 namespace v8 {
 namespace internal {
 
@@ skipping 246 matching lines @@
 }
 
 
 void* RegExpUnparser::VisitCapture(RegExpCapture* that, void* data) {
   os_ << "(^ ";
   that->body()->Accept(this, data);
   os_ << ")";
   return NULL;
 }
 
+void* RegExpUnparser::VisitGroup(RegExpGroup* that, void* data) {
+  os_ << "(?: ";
+  that->body()->Accept(this, data);
+  os_ << ")";
+  return NULL;
+}
 
 void* RegExpUnparser::VisitLookaround(RegExpLookaround* that, void* data) {
   os_ << "(";
   os_ << (that->type() == RegExpLookaround::LOOKAHEAD ? "->" : "<-");
   os_ << (that->is_positive() ? " + " : " - ");
   that->body()->Accept(this, data);
   os_ << ")";
   return NULL;
 }
 
@@ skipping 51 matching lines @@
     int node_min_match = node->min_match();
     min_match_ = IncreaseBy(min_match_, node_min_match);
     int node_max_match = node->max_match();
     max_match_ = IncreaseBy(max_match_, node_max_match);
   }
 }
 
 
 }  // namespace internal
 }  // namespace v8