Give correct value ranges to enumeration types used as opaque types.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index d2f6d3559bf99d37b31b448a1e777a76d933002b..c0fd950145e54db840cae5c590c5d36fc1122ac1 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2762,7 +2762,12 @@ class Code: public HeapObject {
  public:
   // Opaque data type for encapsulating code flags like kind, inline
   // cache state, and arguments count.
-  enum Flags { };
+  // FLAGS_MIN_VALUE and FLAGS_MAX_VALUE are specified to ensure that
+  // enumeration type has correct value range (see Issue 830 for more details).
+  enum Flags {
+    FLAGS_MIN_VALUE = kMinInt,
+    FLAGS_MAX_VALUE = kMaxInt
+  };
 
   enum Kind {
     FUNCTION,