[heap] Make typed slot set state and operations atomic.

test/unittests/heap/slot-set-unittest.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits>
 
 #include "src/globals.h"
 #include "src/heap/slot-set.h"
 #include "src/heap/spaces.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 129 matching lines @@
 }
 
 TEST(TypedSlotSet, Iterate) {
   TypedSlotSet set(0);
   const int kDelta = 10000001;
   const int kHostDelta = 50001;
   int added = 0;
   uint32_t j = 0;
   for (uint32_t i = 0; i < TypedSlotSet::kMaxOffset;
        i += kDelta, j += kHostDelta) {
-    SlotType type = static_cast<SlotType>(i % NUMBER_OF_SLOT_TYPES);
+    SlotType type = static_cast<SlotType>(i % CLEARED_SLOT);
     set.Insert(type, j, i);
     ++added;
   }
   int iterated = 0;
   set.Iterate([&iterated, kDelta, kHostDelta](SlotType type, Address host_addr,
                                               Address addr) {
     uint32_t i = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(addr));
     uint32_t j = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(host_addr));
-    EXPECT_EQ(i % NUMBER_OF_SLOT_TYPES, static_cast<uint32_t>(type));
+    EXPECT_EQ(i % CLEARED_SLOT, static_cast<uint32_t>(type));
     EXPECT_EQ(0, i % kDelta);
     EXPECT_EQ(0, j % kHostDelta);
     ++iterated;
     return i % 2 == 0 ? KEEP_SLOT : REMOVE_SLOT;
   });
   EXPECT_EQ(added, iterated);
   iterated = 0;
   set.Iterate([&iterated](SlotType type, Address host_addr, Address addr) {
     uint32_t i = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(addr));
     EXPECT_EQ(0, i % 2);
     ++iterated;
     return KEEP_SLOT;
   });
   EXPECT_EQ(added / 2, iterated);
 }
 
 }  // namespace internal
 }  // namespace v8