Optimize the typeof operator.

src/interface-descriptors.h

Index: src/interface-descriptors.h
diff --git a/src/interface-descriptors.h b/src/interface-descriptors.h
index a100123e10639274633355c71a06c9ba689115a9..6cf9df2d5805b33ae32a17503d2b06735e37f5a3 100644
--- a/src/interface-descriptors.h
+++ b/src/interface-descriptors.h
@@ -25,6 +25,7 @@ class PlatformInterfaceDescriptor;
   V(FastNewContext)                           \
   V(ToNumber)                                 \
   V(NumberToString)                           \
+  V(Typeof)                                   \
   V(FastCloneShallowArray)                    \
   V(FastCloneShallowObject)                   \
   V(CreateAllocationSite)                     \
@@ -302,6 +303,12 @@ class NumberToStringDescriptor : public CallInterfaceDescriptor {
 };
 
 
+class TypeofDescriptor : public CallInterfaceDescriptor {
+ public:
+  DECLARE_DESCRIPTOR(TypeofDescriptor, CallInterfaceDescriptor)
+};
+
+
 class FastCloneShallowArrayDescriptor : public CallInterfaceDescriptor {
  public:
   DECLARE_DESCRIPTOR(FastCloneShallowArrayDescriptor, CallInterfaceDescriptor)