Add tool to visualize machine code/lithium.

src/x64/lithium-codegen-x64.h

Index: src/x64/lithium-codegen-x64.h
diff --git a/src/x64/lithium-codegen-x64.h b/src/x64/lithium-codegen-x64.h
index e6855637c1c1ba852093791d073eb1a0b57a39b0..f3f202a277ffa1b951cf498bb47096b7853581ee 100644
--- a/src/x64/lithium-codegen-x64.h
+++ b/src/x64/lithium-codegen-x64.h
@@ -60,8 +60,7 @@ class LCodeGen: public LCodeGenBase {
         frame_is_built_(false),
         safepoints_(info->zone()),
         resolver_(this),
-        expected_safepoint_kind_(Safepoint::kSimple),
-        old_position_(RelocInfo::kNoPosition) {
+        expected_safepoint_kind_(Safepoint::kSimple) {
     PopulateDeoptimizationLiteralsWithInlinedFunctions();
   }
 
@@ -256,8 +255,7 @@ class LCodeGen: public LCodeGenBase {
   void RecordSafepointWithRegisters(LPointerMap* pointers,
                                     int arguments,
                                     Safepoint::DeoptMode mode);
-  void RecordPosition(int position);
-  void RecordAndUpdatePosition(int position) V8_OVERRIDE;
+  void RecordAndWritePosition(int position) V8_OVERRIDE;
 
   static Condition TokenToCondition(Token::Value op, bool is_unsigned);
   void EmitGoto(int block);
@@ -346,8 +344,6 @@ class LCodeGen: public LCodeGenBase {
 
   Safepoint::Kind expected_safepoint_kind_;
 
-  int old_position_;
-
   class PushSafepointRegistersScope V8_FINAL BASE_EMBEDDED {
    public:
     explicit PushSafepointRegistersScope(LCodeGen* codegen)