Clean up some uses of Failures and MaybeObjects.

src/v8globals.h

 // 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 331 matching lines @@
     unsigned int sign     :1;
     unsigned int exp      :11;
     unsigned int man_high :20;
     unsigned int man_low  :32;
   } bits;
 };
 
 
 // AccessorCallback
 struct AccessorDescriptor {
-  MaybeObject* (*getter)(Isolate* isolate, Object* object, void* data);
-  MaybeObject* (*setter)(
+  Object* (*getter)(Isolate* isolate, Object* object, void* data);
+  Object* (*setter)(
       Isolate* isolate, JSObject* object, Object* value, void* data);
   void* data;
 };
 
 
 // Logging and profiling.  A StateTag represents a possible state of
 // the VM. The logger maintains a stack of these. Creating a VMState
 // object enters a state by pushing on the stack, and destroying a
 // VMState object leaves a state by popping the current state from the
 // stack.
@@ skipping 198 matching lines @@
 enum MinusZeroMode {
   TREAT_MINUS_ZERO_AS_ZERO,
   FAIL_ON_MINUS_ZERO
 };
 
 } }  // namespace v8::internal
 
 namespace i = v8::internal;
 
 #endif  // V8_V8GLOBALS_H_