Reorganize net/disk_cache into backend specific directories.

net/disk_cache/blockfile/disk_format.h

Index: net/disk_cache/blockfile/disk_format.h
diff --git a/net/disk_cache/disk_format.h b/net/disk_cache/blockfile/disk_format.h
similarity index 96%
rename from net/disk_cache/disk_format.h
rename to net/disk_cache/blockfile/disk_format.h
index 5d7597ab17d5c4c6e78c999b9ba02fd33cfb04f7..95ac58b6274caf2c969266f77b2ce5b5813db346 100644
--- a/net/disk_cache/disk_format.h
+++ b/net/disk_cache/blockfile/disk_format.h
@@ -42,12 +42,12 @@
 // being currently used, it means that the entry was not properly closed on a
 // previous run, so it is discarded.
 
-#ifndef NET_DISK_CACHE_DISK_FORMAT_H_
-#define NET_DISK_CACHE_DISK_FORMAT_H_
+#ifndef NET_DISK_CACHE_BLOCKFILE_DISK_FORMAT_H_
+#define NET_DISK_CACHE_BLOCKFILE_DISK_FORMAT_H_
 
 #include "base/basictypes.h"
 #include "net/base/net_export.h"
-#include "net/disk_cache/disk_format_base.h"
+#include "net/disk_cache/blockfile/disk_format_base.h"
 
 namespace disk_cache {
 
@@ -150,4 +150,4 @@ COMPILE_ASSERT(sizeof(RankingsNode) == 36, bad_RankingsNode);
 
 }  // namespace disk_cache
 
-#endif  // NET_DISK_CACHE_DISK_FORMAT_H_
+#endif  // NET_DISK_CACHE_BLOCKFILE_DISK_FORMAT_H_