Revert r12825 and r12796 from trunk.

src/objects-debug.cc

 // Copyright 2012 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 481 matching lines @@
   CHECK(!this->parent()->IsSlicedString());
   CHECK(this->length() >= SlicedString::kMinLength);
 }
 
 
 void JSFunction::JSFunctionVerify() {
   CHECK(IsJSFunction());
   VerifyObjectField(kPrototypeOrInitialMapOffset);
   VerifyObjectField(kNextFunctionLinkOffset);
   CHECK(code()->IsCode());
-  CHECK(next_function_link() == NULL ||
-        next_function_link()->IsUndefined() ||
+  CHECK(next_function_link()->IsUndefined() ||
         next_function_link()->IsJSFunction());
 }
 
 
 void SharedFunctionInfo::SharedFunctionInfoVerify() {
   CHECK(IsSharedFunctionInfo());
   VerifyObjectField(kNameOffset);
   VerifyObjectField(kCodeOffset);
   VerifyObjectField(kOptimizedCodeMapOffset);
   VerifyObjectField(kScopeInfoOffset);
@@ skipping 488 matching lines @@
   for (int i = 0; i < number_of_transitions(); ++i) {
     if (!CheckOneBackPointer(current_map, GetTarget(i))) return false;
   }
   return true;
 }
 
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal