Hide heap methods where possible.

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 389789f7e85ca533c09a01500ddc204d90049986..e2c120aae6a80decd299c2e8bfa4d846018c436b 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -1328,9 +1328,9 @@ Handle<JSObject> Factory::NewExternal(void* value) {
 }
 
 
-Handle<Code> NewCodeHelper(Isolate* isolate, int object_size, bool immovable) {
-  CALL_HEAP_FUNCTION(isolate,
-                     isolate->heap()->AllocateCode(object_size, immovable),
+Handle<Code> Factory::NewCodeHelper(int object_size, bool immovable) {
+  CALL_HEAP_FUNCTION(isolate(),
+                     isolate()->heap()->AllocateCode(object_size, immovable),
                      Code);
 }
 
@@ -1349,7 +1349,7 @@ Handle<Code> Factory::NewCode(const CodeDesc& desc,
   int body_size = RoundUp(desc.instr_size, kObjectAlignment);
   int obj_size = Code::SizeFor(body_size);
 
-  Handle<Code> code = NewCodeHelper(isolate(), obj_size, immovable);
+  Handle<Code> code = NewCodeHelper(obj_size, immovable);
   ASSERT(!isolate()->code_range()->exists() ||
          isolate()->code_range()->contains(code->address()));