Disk cache: Avoid writing uninitialized data to disk.

net/disk_cache/stats.cc

Index: net/disk_cache/stats.cc
===================================================================
--- net/disk_cache/stats.cc	(revision 201943)
+++ net/disk_cache/stats.cc	(working copy)
@@ -207,10 +207,10 @@
   return total;
 }
 
-bool Stats::SerializeStats(void* data, int num_bytes, Addr* address) {
+int Stats::SerializeStats(void* data, int num_bytes, Addr* address) {
   OnDiskStats* stats = reinterpret_cast<OnDiskStats*>(data);
   if (num_bytes < static_cast<int>(sizeof(*stats)))
-    return false;
+    return 0;
 
   stats->signature = kDiskSignature;
   stats->size = sizeof(stats);
@@ -218,7 +218,7 @@
   memcpy(stats->counters, counters_, sizeof(counters_));
 
   *address = storage_addr_;
-  return true;
+  return sizeof(*stats);
 }
 
 int Stats::GetBucketRange(size_t i) const {