Remove JSReceiver::GetPrototype and replace it with PrototypeIterator calls

src/isolate.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdlib.h>
 
 #include "src/v8.h"
 
 #include "src/ast.h"
 #include "src/base/platform/platform.h"
@@ skipping 2138 matching lines @@
   JSObject* initial_array_proto = JSObject::cast(*initial_array_prototype());
 
   // Check that the array prototype hasn't been altered WRT empty elements.
   if (root_array_map->prototype() != initial_array_proto) return false;
   if (initial_array_proto->elements() != heap()->empty_fixed_array()) {
     return false;
   }
 
   // Check that the object prototype hasn't been altered WRT empty elements.
   JSObject* initial_object_proto = JSObject::cast(*initial_object_prototype());
-  Object* root_array_map_proto = initial_array_proto->GetPrototype();
-  if (root_array_map_proto != initial_object_proto) return false;
+  PrototypeIterator iter(this, initial_array_proto);
+  if (iter.IsAtEnd() || iter.GetCurrent() != initial_object_proto) {
+    return false;
+  }
   if (initial_object_proto->elements() != heap()->empty_fixed_array()) {
     return false;
   }
 
-  return initial_object_proto->GetPrototype()->IsNull();
+  iter.Advance();
+  return iter.IsAtEnd();
 }
 
 
 CodeStubInterfaceDescriptor*
     Isolate::code_stub_interface_descriptor(int index) {
   return code_stub_interface_descriptors_ + index;
 }
 
 
 CallInterfaceDescriptor*
@@ skipping 172 matching lines @@
   if (prev_ && prev_->Intercept(flag)) return true;
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 } }  // namespace v8::internal