Update the gap resolver to support Smi constants.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index adbe64cb27fbec70d31ffd9029f2e0afd4572252..925ecc56b624d3829cddc38869122d43d42e3b4e 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -453,6 +453,12 @@ int LCodeGen::ToInteger32(LConstantOperand* op) const {
 }
 
 
+Smi* LCodeGen::ToSmi(LConstantOperand* op) const {
+  HConstant* constant = chunk_->LookupConstant(op);
+  return Smi::FromInt(constant->Integer32Value());
+}
+
+
 double LCodeGen::ToDouble(LConstantOperand* op) const {
   HConstant* constant = chunk_->LookupConstant(op);
   ASSERT(constant->HasDoubleValue());