MIPS: Fix and simplify code aging.

src/mips/assembler-mips-inl.h

Index: src/mips/assembler-mips-inl.h
diff --git a/src/mips/assembler-mips-inl.h b/src/mips/assembler-mips-inl.h
index d5af5b2ec6d2521ea85a3a7129ad4a108874e68f..514b3aaa4f00247abdf680935b18edaedcbe3efc 100644
--- a/src/mips/assembler-mips-inl.h
+++ b/src/mips/assembler-mips-inl.h
@@ -260,16 +260,14 @@ Handle<Object> RelocInfo::code_age_stub_handle(Assembler* origin) {
 Code* RelocInfo::code_age_stub() {
   ASSERT(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
   return Code::GetCodeFromTargetAddress(
-      Memory::Address_at(pc_ + Assembler::kInstrSize *
-                         (kNoCodeAgeSequenceLength - 1)));
+      Assembler::target_address_at(pc_ + Assembler::kInstrSize));
 }
 
 
 void RelocInfo::set_code_age_stub(Code* stub) {
   ASSERT(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
-  Memory::Address_at(pc_ + Assembler::kInstrSize *
-                     (kNoCodeAgeSequenceLength - 1)) =
-      stub->instruction_start();
+  Assembler::set_target_address_at(pc_ + Assembler::kInstrSize,
+                                   stub->instruction_start());
 }