Use page header information to test for InNewSpace.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index dcc1c5339c331469a118e80424c323fd2ec54da1..68361385edf319533ed3b6c4a70fec7034417989 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -618,6 +618,7 @@ enum CompareResult {
 
 class StringStream;
 class ObjectVisitor;
+class Failure;
 
 struct ValueInfo : public Malloced {
   ValueInfo() : type(FIRST_TYPE), ptr(NULL), str(NULL), number(0) { }
@@ -631,7 +632,6 @@ struct ValueInfo : public Malloced {
 // A template-ized version of the IsXXX functions.
 template <class C> static inline bool Is(Object* obj);
 
-
 class MaybeObject BASE_EMBEDDED {
  public:
   inline bool IsFailure();
@@ -644,6 +644,10 @@ class MaybeObject BASE_EMBEDDED {
     *obj = reinterpret_cast<Object*>(this);
     return true;
   }
+  inline Failure* ToFailureUnchecked() {
+    ASSERT(IsFailure());
+    return reinterpret_cast<Failure*>(this);
+  }
   inline Object* ToObjectUnchecked() {
     ASSERT(!IsFailure());
     return reinterpret_cast<Object*>(this);