Merge a number of assertion failure fixes to the 3.0 branch.

src/objects.h

 // Copyright 2010 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 1561 matching lines @@
   // Lookup a property.  If found, the result is valid and has
   // detailed information.
   void LocalLookup(String* name, LookupResult* result);
   void Lookup(String* name, LookupResult* result);
 
   // The following lookup functions skip interceptors.
   void LocalLookupRealNamedProperty(String* name, LookupResult* result);
   void LookupRealNamedProperty(String* name, LookupResult* result);
   void LookupRealNamedPropertyInPrototypes(String* name, LookupResult* result);
   void LookupCallbackSetterInPrototypes(String* name, LookupResult* result);
-  bool SetElementWithCallbackSetterInPrototypes(uint32_t index, Object* value);
+  MUST_USE_RESULT MaybeObject* SetElementWithCallbackSetterInPrototypes(
+      uint32_t index, Object* value, bool* found);
   void LookupCallback(String* name, LookupResult* result);
 
   // Returns the number of properties on this object filtering out properties
   // with the specified attributes (ignoring interceptors).
   int NumberOfLocalProperties(PropertyAttributes filter);
   // Returns the number of enumerable properties (ignoring interceptors).
   int NumberOfEnumProperties();
   // Fill in details for properties into storage starting at the specified
   // index.
   void GetLocalPropertyNames(FixedArray* storage, int index);
@@ skipping 4899 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_