Add new simple disk cache backend.

net/disk_cache/very_simple/very_simple_disk_format.h

+// 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.
+
+#ifndef NET_DISK_CACHE_VERY_SIMPLE_VERY_SIMPLE_DISK_FORMAT_H_
+#define NET_DISK_CACHE_VERY_SIMPLE_VERY_SIMPLE_DISK_FORMAT_H_
+
+namespace disk_cache {
+
+const uint64 kVerySimpleInitialMagicNumber = 0x10adab1ebeef;

[rvargas (doing something else), 2013/02/06 03:28:40]

nit: something vegetarian? Seriously, avoid common patterns.

[gavinp, 2013/02/08 23:17:51]

Not so common: http://www.bing.com/search?q=0x10adab1ebeef

Now replaced with a random number.

+
+// A file in the VerySimple cache consists of a VerySimpleFileHeader followed
+// by data.
+
+const uint32 kVerySimpleVersion = 0;

[rvargas (doing something else), 2013/02/06 03:28:40]

nit: 0?

[gavinp, 2013/02/08 23:17:51]

Now 1.

+
+struct VerySimpleFileHeader {
+  uint64 initial_magic_number;
+  uint32 version;
+  uint32 key_length;
+  uint32 key_murmur3;
+};
+
+}  // namespace disk_cache
+
+#endif  // NET_DISK_CACHE_VERY_SIMPLE_VERY_SIMPLE_DISK_FORMAT_H_