Make Failure inherit from MaybeObject instead of Object.

src/runtime.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 468 matching lines @@
     // Size of result.  Most functions return a single pointer, size 1.
     int result_size;
   };
 
   static const int kNotFound = -1;
 
   // Add symbols for all the intrinsic function names to a StringDictionary.
   // Returns failure if an allocation fails.  In this case, it must be
   // retried with a new, empty StringDictionary, not with the same one.
   // Alternatively, heap initialization can be completely restarted.
-  static Object* InitializeIntrinsicFunctionNames(Object* dictionary);
+  MUST_USE_RESULT static MaybeObject* InitializeIntrinsicFunctionNames(
+      Object* dictionary);
 
   // Get the intrinsic function with the given name, which must be a symbol.
   static Function* FunctionForSymbol(Handle<String> name);
 
   // Get the intrinsic function with the given FunctionId.
   static Function* FunctionForId(FunctionId id);
 
   // General-purpose helper functions for runtime system.
   static int StringMatch(Handle<String> sub, Handle<String> pat, int index);
 
   static bool IsUpperCaseChar(uint16_t ch);
 
   // TODO(1240886): The following three methods are *not* handle safe,
   // but accept handle arguments. This seems fragile.
 
   // Support getting the characters in a string using [] notation as
   // in Firefox/SpiderMonkey, Safari and Opera.
-  static Object* GetElementOrCharAt(Handle<Object> object, uint32_t index);
-  static Object* GetElement(Handle<Object> object, uint32_t index);
+  MUST_USE_RESULT static MaybeObject* GetElementOrCharAt(Handle<Object> object,
+                                                         uint32_t index);
+  MUST_USE_RESULT static MaybeObject* GetElement(Handle<Object> object,
+                                                 uint32_t index);
 
-  static Object* SetObjectProperty(Handle<Object> object,
-                                   Handle<Object> key,
-                                   Handle<Object> value,
-                                   PropertyAttributes attr);
+  MUST_USE_RESULT static MaybeObject* SetObjectProperty(
+      Handle<Object> object,
+      Handle<Object> key,
+      Handle<Object> value,
+      PropertyAttributes attr);
 
-  static Object* ForceSetObjectProperty(Handle<JSObject> object,
-                                        Handle<Object> key,
-                                        Handle<Object> value,
-                                        PropertyAttributes attr);
+  MUST_USE_RESULT static MaybeObject* ForceSetObjectProperty(
+      Handle<JSObject> object,
+      Handle<Object> key,
+      Handle<Object> value,
+      PropertyAttributes attr);
 
-  static Object* ForceDeleteObjectProperty(Handle<JSObject> object,
-                                           Handle<Object> key);
+  MUST_USE_RESULT static MaybeObject* ForceDeleteObjectProperty(
+      Handle<JSObject> object,
+      Handle<Object> key);
 
-  static Object* GetObjectProperty(Handle<Object> object, Handle<Object> key);
+  MUST_USE_RESULT static MaybeObject* GetObjectProperty(Handle<Object> object,
+                                                        Handle<Object> key);
 
   // This function is used in FunctionNameUsing* tests.
   static Object* FindSharedFunctionInfoInScript(Handle<Script> script,
                                                 int position);
 
   // Helper functions used stubs.
   static void PerformGC(Object* result);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_RUNTIME_H_