Disk cache: Avoid writing uninitialized data to disk.

net/disk_cache/stats.h

 // Copyright (c) 2012 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.
 
 #ifndef NET_DISK_CACHE_STATS_H_
 #define NET_DISK_CACHE_STATS_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 62 matching lines @@
 
   void GetItems(StatsItems* items);
   int GetHitRatio() const;
   int GetResurrectRatio() const;
   void ResetRatios();
 
   // Returns the lower bound of the space used by entries bigger than 512 KB.
   int GetLargeEntriesSize();
 
   // Writes the stats into |data|, to be stored at the given cache address.
-  bool SerializeStats(void* data, int num_bytes, Addr* address);
+  // Returns the number of bytes copied.
+  int SerializeStats(void* data, int num_bytes, Addr* address);
 
   // Support for StatsHistograms. Together, these methods allow StatsHistograms
   // to take a snapshot of the data_sizes_ as the histogram data.
   int GetBucketRange(size_t i) const;
   void Snapshot(base::HistogramSamples* samples) const;
 
  private:
   int GetStatsBucket(int32 size);
   int GetRatio(Counters hit, Counters miss) const;
 
   Addr storage_addr_;
   int data_sizes_[kDataSizesLength];
   int64 counters_[MAX_COUNTER];
   StatsHistogram* size_histogram_;
 
   DISALLOW_COPY_AND_ASSIGN(Stats);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_STATS_H_