Make Failure inherit from MaybeObject instead of Object.

src/spaces-inl.h

Index: src/spaces-inl.h
===================================================================
--- src/spaces-inl.h	(revision 5696)
+++ src/spaces-inl.h	(working copy)
@@ -430,7 +430,7 @@
 
 
 // Raw allocation.
-Object* PagedSpace::AllocateRaw(int size_in_bytes) {
+MaybeObject* PagedSpace::AllocateRaw(int size_in_bytes) {
   ASSERT(HasBeenSetup());
   ASSERT_OBJECT_SIZE(size_in_bytes);
   HeapObject* object = AllocateLinearly(&allocation_info_, size_in_bytes);
@@ -444,7 +444,7 @@
 
 
 // Reallocating (and promoting) objects during a compacting collection.
-Object* PagedSpace::MCAllocateRaw(int size_in_bytes) {
+MaybeObject* PagedSpace::MCAllocateRaw(int size_in_bytes) {
   ASSERT(HasBeenSetup());
   ASSERT_OBJECT_SIZE(size_in_bytes);
   HeapObject* object = AllocateLinearly(&mc_forwarding_info_, size_in_bytes);
@@ -471,8 +471,8 @@
 // -----------------------------------------------------------------------------
 // LargeObjectSpace
 
-Object* NewSpace::AllocateRawInternal(int size_in_bytes,
-                                      AllocationInfo* alloc_info) {
+MaybeObject* NewSpace::AllocateRawInternal(int size_in_bytes,
+                                           AllocationInfo* alloc_info) {
   Address new_top = alloc_info->top + size_in_bytes;
   if (new_top > alloc_info->limit) return Failure::RetryAfterGC();