Avoid fragmenting the heap too much while reconstructing the index.

net/disk_cache/simple/simple_util.h

Index: net/disk_cache/simple/simple_util.h
diff --git a/net/disk_cache/simple/simple_util.h b/net/disk_cache/simple/simple_util.h
index 2e92b4a049d8c676cff433e857d40d81f1ec0e45..3bb80b9540238393aa859a9791e6a4faab7d458f 100644
--- a/net/disk_cache/simple/simple_util.h
+++ b/net/disk_cache/simple/simple_util.h
@@ -8,6 +8,7 @@
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/strings/string_piece.h"
 #include "net/base/net_export.h"
 
 namespace base {
@@ -33,7 +34,7 @@ NET_EXPORT_PRIVATE uint64 GetEntryHashKey(const std::string& key);
 // Parses the |hash_key| string into a uint64 buffer.
 // |hash_key| string must be of the form: FFFFFFFFFFFFFFFF .
 NET_EXPORT_PRIVATE bool GetEntryHashKeyFromHexString(
-    const std::string& hash_key,
+    const base::StringPiece& hash_key,
     uint64* hash_key_out);
 
 // Given a |key| for a (potential) entry in the simple backend and the |index|