This is a little experiment to move Failure to a superclass above Object...

src/objects.h

Index: src/objects.h
===================================================================
--- src/objects.h	(revision 5559)
+++ src/objects.h	(working copy)
@@ -585,13 +585,26 @@
 template <class C> static inline bool Is(Object* obj);
 
 
+class Object;
+
+
+class TryAllocation BASE_EMBEDDED {
+ public:
+  inline bool ToObject(Object** out) {
+    if (this->IsFailure()) return false;
+    *out = Object::cast(this);
+    return true;
+  }
+};
+
+
 // Object is the abstract superclass for all classes in the
 // object hierarchy.
 // Object does not use any virtual functions to avoid the
 // allocation of the C++ vtable.
 // Since Smi and Failure are subclasses of Object no
 // data members can be present in Object.
-class Object BASE_EMBEDDED {
+class Object : public TryAllocation {
  public:
   // Type testing.
   inline bool IsSmi();
@@ -619,7 +632,6 @@
   inline bool IsExternalIntArray();
   inline bool IsExternalUnsignedIntArray();
   inline bool IsExternalFloatArray();
-  inline bool IsFailure();
   inline bool IsRetryAfterGC();
   inline bool IsOutOfMemoryFailure();
   inline bool IsException();
@@ -820,7 +832,7 @@
 const int kFailureTypeTagSize = 2;
 const int kFailureTypeTagMask = (1 << kFailureTypeTagSize) - 1;
 
-class Failure: public Object {
+class Failure: public TryAllocation {
  public:
   // RuntimeStubs assumes EXCEPTION = 1 in the compiler-generated code.
   enum Type {
@@ -1282,7 +1294,7 @@
   Object* PrepareElementsForSort(uint32_t limit);
   // As PrepareElementsForSort, but only on objects where elements is
   // a dictionary, and it will stay a dictionary.
-  MUST_USE_RESULT Object* PrepareSlowElementsForSort(uint32_t limit);
+  TryAllocation* PrepareSlowElementsForSort(uint32_t limit);
 
   Object* SetProperty(String* key,
                       Object* value,