Add fast paths for Smi values in the dart embedding api.

vm/object.cc

Index: vm/object.cc
===================================================================
--- vm/object.cc	(revision 6600)
+++ vm/object.cc	(working copy)
@@ -6699,16 +6699,6 @@
 }
 
 
-bool Smi::IsValid(intptr_t value) {
-  return (value >= kMinValue) && (value <= kMaxValue);
-}
-
-
-bool Smi::IsValid64(int64_t value) {
-  return (value >= kMinValue) && (value <= kMaxValue);
-}
-
-
 double Smi::AsDoubleValue() const {
   return static_cast<double>(this->Value());
 }