Need to update last_slot when unprovisioned_bytes && discard.

base/allocator/partition_allocator/partition_alloc.cc

 // Copyright (c) 2013 The Chromium 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 "base/allocator/partition_allocator/partition_alloc.h"
 
 #include <string.h>
 
 #include "base/allocator/partition_allocator/oom.h"
 #include "base/allocator/partition_allocator/spin_lock.h"
@@ skipping 1144 matching lines @@
     // Rewrite the freelist.
     PartitionFreelistEntry** entry_ptr = &page->freelist_head;
     for (size_t slotIndex = 0; slotIndex < num_slots; ++slotIndex) {
       if (slot_usage[slotIndex])
         continue;
       PartitionFreelistEntry* entry = reinterpret_cast<PartitionFreelistEntry*>(
           ptr + (slot_size * slotIndex));
       *entry_ptr = PartitionFreelistMask(entry);
       entry_ptr = reinterpret_cast<PartitionFreelistEntry**>(entry);
       num_new_entries++;
+      last_slot = slotIndex;
     }
     // Terminate the freelist chain.
     *entry_ptr = nullptr;
     // The freelist head is stored unmasked.
     page->freelist_head = PartitionFreelistMask(page->freelist_head);
     DCHECK(num_new_entries == num_slots - page->num_allocated_slots);
     // Discard the memory.
     DiscardSystemPages(begin_ptr, unprovisioned_bytes);
   }
 
@@ skipping 262 matching lines @@
     // can use PartitionAlloc to allocate and this can affect the statistics.
     for (size_t i = 0; i < partitionNumBuckets; ++i) {
       if (memory_stats[i].is_valid)
         dumper->PartitionsDumpBucketStats(partition_name, &memory_stats[i]);
     }
   }
   dumper->PartitionDumpTotals(partition_name, &stats);
 }
 
 }  // namespace base