Make whether or not a Code object should be created by masm explicit

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index fbbc0688e1ce2453a35c66d797d221059f867d6f..68d110b89c0dd4a1f163361816e37d142a470fd9 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -17,12 +17,13 @@
 namespace v8 {
 namespace internal {
 
-MacroAssembler::MacroAssembler(Isolate* arg_isolate, void* buffer, int size)
+MacroAssembler::MacroAssembler(Isolate* arg_isolate, void* buffer, int size,
+                               bool create_code_object)
     : Assembler(arg_isolate, buffer, size),
       generating_stub_(false),
       has_frame_(false),
       root_array_available_(true) {
-  if (isolate() != NULL) {
+  if (create_code_object) {
     code_object_ =
         Handle<Object>::New(isolate()->heap()->undefined_value(), isolate());
   }
@@ -5190,7 +5191,7 @@ bool AreAliased(Register reg1,
 CodePatcher::CodePatcher(byte* address, int size)
     : address_(address),
       size_(size),
-      masm_(NULL, address, size + Assembler::kGap) {
+      masm_(NULL, address, size + Assembler::kGap, false) {
   // Create a new macro assembler pointing to the address of the code to patch.
   // The size is adjusted with kGap on order for the assembler to generate size
   // bytes of instructions without failing with buffer size constraints.