Harden allocator for file-backed memory.

base/metrics/persistent_histogram_allocator.cc

 // Copyright 2016 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/metrics/persistent_histogram_allocator.h"
 
 #include <memory>
 
 #include "base/atomicops.h"
 #include "base/files/file_path.h"
@@ skipping 887 matching lines @@
     LOG(ERROR) << "Could not write \"" << Name() << "\" persistent histograms"
                << " to file: " << persistent_location_.value();
     return false;
   }
 
   return true;
 #endif
 }
 
 void GlobalHistogramAllocator::DeletePersistentLocation() {
+  memory_allocator()->SetMemoryState(PersistentMemoryAllocator::MEMORY_DELETED);
+
 #if defined(OS_NACL)
   NOTREACHED();
 #else
   if (persistent_location_.empty())
     return;
 
   // Open (with delete) and then immediately close the file by going out of
   // scope. This is the only cross-platform safe way to delete a file that may
   // be open elsewhere. Open handles will continue to operate normally but
   // new opens will not be possible.
@@ skipping 26 matching lines @@
   while (true) {
     std::unique_ptr<HistogramBase> histogram =
         import_iterator_.GetNextWithIgnore(record_to_ignore);
     if (!histogram)
       break;
     StatisticsRecorder::RegisterOrDeleteDuplicate(histogram.release());
   }
 }
 
 }  // namespace base