Fix IsDeletable() for HStringAdd, HStringCharCodeAt, HStringCharFromCode.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 20430c39c7790aab694480b5c3c48f08c7ff20a8..3eca181c6fac57f9da076bb9f4e35a4bf5a53d0b 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -3718,11 +3718,6 @@ Representation HUnaryMathOperation::RepresentationFromInputs() {
 }
 
 
-HType HStringCharFromCode::CalculateInferredType() {
-  return HType::String();
-}
-
-
 void HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
                                           HValue* dominator) {
   ASSERT(side_effect == kChangesNewSpacePromotion);