Rehash and clear deleted entries in weak collections during GC

test/cctest/test-weakmaps.cc

 // Copyright 2011 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 106 matching lines @@
   // Perform two consecutive GCs because the first one will only clear
   // weak references whereas the second one will also clear weak maps.
   heap->CollectAllGarbage(false);
   CHECK_EQ(1, NumberOfWeakCalls);
   CHECK_EQ(2, ObjectHashTable::cast(weakmap->table())->NumberOfElements());
   CHECK_EQ(
       0, ObjectHashTable::cast(weakmap->table())->NumberOfDeletedElements());
   heap->CollectAllGarbage(false);
   CHECK_EQ(1, NumberOfWeakCalls);
   CHECK_EQ(0, ObjectHashTable::cast(weakmap->table())->NumberOfElements());
-  CHECK_EQ(2,
+  CHECK_EQ(0,
            ObjectHashTable::cast(weakmap->table())->NumberOfDeletedElements());
 }
 
 
 TEST(Shrinking) {
   LocalContext context;
   Isolate* isolate = GetIsolateFrom(&context);
   Factory* factory = isolate->factory();
   Heap* heap = isolate->heap();
   HandleScope scope(isolate);
@@ skipping 120 matching lines @@
   {
     HandleScope scope(isolate);
     AllocateJSWeakMap(isolate);
     SimulateIncrementalMarking(heap);
   }
   // The weak map is marked black here but leaving the handle scope will make
   // the object unreachable. Aborting incremental marking will clear all the
   // marking bits which makes the weak map garbage.
   heap->CollectAllGarbage();
 }