Move some code from Runtime_GetPrototype into a new Object::GetPrototype.

src/runtime/runtime-debug.cc

Index: src/runtime/runtime-debug.cc
diff --git a/src/runtime/runtime-debug.cc b/src/runtime/runtime-debug.cc
index f47d47b8f39862bd6b7b95fca10f7415944999b2..9e78f526dd7c472255137e664ede098b43f7dd08 100644
--- a/src/runtime/runtime-debug.cc
+++ b/src/runtime/runtime-debug.cc
@@ -1452,7 +1452,7 @@ RUNTIME_FUNCTION(Runtime_DebugGetPrototype) {
   HandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, obj, 0);
-  return *Object::GetPrototypeSkipHiddenPrototypes(isolate, obj);
+  return *Object::GetPrototypeWithAccess(isolate, obj);

[neis, 2015/10/13 14:55:54]

Is it correct to not do an access check here?  If not (i.e. this should be a
call to GetPrototype), then is it worth having GetPrototypeWithAccess at all? 
The only other place where it's used is in Runtime_SetPrototype, in order to
avoid two redundant checks.

[Toon Verwaest, 2015/10/14 10:56:18]

Given that the other 2 cases deal with Object.observe, it might be worthwhile to
just drop that function.

 }