Remove redundant NULL check.

src/objects.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 12752 matching lines @@
                           object->TransitionElementsKind(to_kind));
 }
 
 
 const double AllocationSite::kPretenureRatio = 0.60;
 
 
 bool AllocationSite::IsNestedSite() {
   ASSERT(FLAG_trace_track_allocation_sites);
   Object* current = GetHeap()->allocation_sites_list();
-  while (current != NULL && current->IsAllocationSite()) {
+  while (current->IsAllocationSite()) {
     AllocationSite* current_site = AllocationSite::cast(current);
     if (current_site->nested_site() == this) {
       return true;
     }
     current = current_site->weak_next();
   }
   return false;
 }
 
 
@@ skipping 3848 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal