Fix two-char hash to use correct fallback for zero hashes.

src/objects.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 12065 matching lines @@
     hash += hash << 10;
     hash ^= hash >> 6;
     // Char 2.
     hash += c2;
     hash += hash << 10;
     hash ^= hash >> 6;
     // GetHash.
     hash += hash << 3;
     hash ^= hash >> 11;
     hash += hash << 15;
-    if ((hash & String::kHashBitMask) == 0) hash = String::kZeroHash;
+    if ((hash & String::kHashBitMask) == 0) hash = StringHasher::kZeroHash;
 #ifdef DEBUG
     StringHasher hasher(2, seed);
     hasher.AddCharacter(c1);
     hasher.AddCharacter(c2);
     // If this assert fails then we failed to reproduce the two-character
     // version of the string hashing algorithm above.  One reason could be
     // that we were passed two digits as characters, since the hash
     // algorithm is different in that case.
     ASSERT_EQ(static_cast<int>(hasher.GetHash()), static_cast<int>(hash));
 #endif
@@ skipping 1378 matching lines @@
   set_year(Smi::FromInt(year), SKIP_WRITE_BARRIER);
   set_month(Smi::FromInt(month), SKIP_WRITE_BARRIER);
   set_day(Smi::FromInt(day), SKIP_WRITE_BARRIER);
   set_weekday(Smi::FromInt(weekday), SKIP_WRITE_BARRIER);
   set_hour(Smi::FromInt(hour), SKIP_WRITE_BARRIER);
   set_min(Smi::FromInt(min), SKIP_WRITE_BARRIER);
   set_sec(Smi::FromInt(sec), SKIP_WRITE_BARRIER);
 }
 
 } }  // namespace v8::internal