Optimize the typeof operator.

src/code-stubs.cc

Index: src/code-stubs.cc
diff --git a/src/code-stubs.cc b/src/code-stubs.cc
index e3940dad649cb1de5b44bcb29431495d1afc58d5..13ebfa048931326b9ef503261e88337c36c5de9e 100644
--- a/src/code-stubs.cc
+++ b/src/code-stubs.cc
@@ -633,6 +633,9 @@ void FastNewClosureStub::InitializeDescriptor(CodeStubDescriptor* descriptor) {
 void FastNewContextStub::InitializeDescriptor(CodeStubDescriptor* d) {}
 
 
+void TypeofStub::InitializeDescriptor(CodeStubDescriptor* descriptor) {}
+
+
 void NumberToStringStub::InitializeDescriptor(CodeStubDescriptor* descriptor) {
   NumberToStringDescriptor call_descriptor(isolate());
   descriptor->Initialize(
@@ -715,6 +718,12 @@ void StringAddStub::InitializeDescriptor(CodeStubDescriptor* descriptor) {
 }
 
 
+void TypeofStub::GenerateAheadOfTime(Isolate* isolate) {
+  TypeofStub stub(isolate);
+  stub.GetCode();
+}
+
+
 void CreateAllocationSiteStub::GenerateAheadOfTime(Isolate* isolate) {
   CreateAllocationSiteStub stub(isolate);
   stub.GetCode();