Added a simple dead code removal phase.

src/property-details.h

Index: src/property-details.h
diff --git a/src/property-details.h b/src/property-details.h
index b8fbb3c92a8d413822c6d1bb3ea23d14d20524c9..64e320514e3ca41f0a3bc7275ffa2718abf19761 100644
--- a/src/property-details.h
+++ b/src/property-details.h
@@ -96,7 +96,9 @@ class PropertyDetails BASE_EMBEDDED {
 
   PropertyType type() { return TypeField::decode(value_); }
 
-  PropertyAttributes attributes() { return AttributesField::decode(value_); }
+  PropertyAttributes attributes() const {
+    return AttributesField::decode(value_);
+  }
 
   int dictionary_index() {
     return DictionaryStorageField::decode(value_);
@@ -112,10 +114,10 @@ class PropertyDetails BASE_EMBEDDED {
     return DictionaryStorageField::is_valid(index);
   }
 
-  bool IsReadOnly() { return (attributes() & READ_ONLY) != 0; }
-  bool IsDontDelete() { return (attributes() & DONT_DELETE) != 0; }
-  bool IsDontEnum() { return (attributes() & DONT_ENUM) != 0; }
-  bool IsDeleted() { return DeletedField::decode(value_) != 0;}
+  bool IsReadOnly() const { return (attributes() & READ_ONLY) != 0; }
+  bool IsDontDelete() const { return (attributes() & DONT_DELETE) != 0; }
+  bool IsDontEnum() const { return (attributes() & DONT_ENUM) != 0; }
+  bool IsDeleted() const { return DeletedField::decode(value_) != 0;}
 
   // Bit fields in value_ (type, shift, size). Must be public so the
   // constants can be embedded in generated code.