RegExp replace with empty string optimization by Sandholm.

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index f6b93b0773cfa15f92ab88b21466ab0314e0ae99..39e881ac3d567b5fbdc3d354325cc62b4ea994c5 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -96,6 +96,12 @@ Handle<String> Factory::NewStringFromTwoByte(Vector<const uc16> string,
 }
 
 
+Handle<String> Factory::NewRawAsciiString(int length,
+                                          PretenureFlag pretenure) {
+  CALL_HEAP_FUNCTION(Heap::AllocateRawAsciiString(length, pretenure), String);
+}
+
+
 Handle<String> Factory::NewRawTwoByteString(int length,
                                             PretenureFlag pretenure) {
   CALL_HEAP_FUNCTION(Heap::AllocateRawTwoByteString(length, pretenure), String);