Remove the LookupResult IsValid method because it is confusing....

src/property.h

Index: src/property.h
===================================================================
--- src/property.h	(revision 3900)
+++ src/property.h	(working copy)
@@ -201,23 +201,17 @@
   }
 
   JSObject* holder() {
-    ASSERT(IsValid());
+    ASSERT(IsFound());
     return holder_;
   }
 
   PropertyType type() {
-    ASSERT(IsValid());
+    ASSERT(IsFound());
     return details_.type();
   }
 
-  bool IsTransitionType() {
-    PropertyType t = type();
-    if (t == MAP_TRANSITION || t == CONSTANT_TRANSITION) return true;
-    return false;
-  }
-
   PropertyAttributes GetAttributes() {
-    ASSERT(IsValid());
+    ASSERT(IsFound());
     return details_.attributes();
   }
 
@@ -229,16 +223,19 @@
   bool IsDontDelete() { return details_.IsDontDelete(); }
   bool IsDontEnum() { return details_.IsDontEnum(); }
   bool IsDeleted() { return details_.IsDeleted(); }
+  bool IsFound() { return lookup_type_ != NOT_FOUND; }
 
-  bool IsValid() { return  lookup_type_ != NOT_FOUND; }
-  bool IsNotFound() { return lookup_type_ == NOT_FOUND; }
-
-  // Tells whether the result is a property.
-  // Excluding transitions and the null descriptor.
+  // Is the result is a property excluding transitions and the null
+  // descriptor?
   bool IsProperty() {
-    return IsValid() && type() < FIRST_PHANTOM_PROPERTY_TYPE;
+    return IsFound() && (type() < FIRST_PHANTOM_PROPERTY_TYPE);
   }
 
+  // Is the result a property or a transition?
+  bool IsPropertyOrTransition() {
+    return IsFound() && (type() != NULL_DESCRIPTOR);
+  }
+
   bool IsCacheable() { return cacheable_; }
   void DisallowCaching() { cacheable_ = false; }