Reorganize net/disk_cache into backend specific directories.

net/disk_cache/blockfile/rankings.cc

Index: net/disk_cache/blockfile/rankings.cc
diff --git a/net/disk_cache/rankings.cc b/net/disk_cache/blockfile/rankings.cc
similarity index 98%
rename from net/disk_cache/rankings.cc
rename to net/disk_cache/blockfile/rankings.cc
index 636bbcf920812c445b7ac51bab654b459dd605a1..2a034819da975ddcca1fed151a52fe2e4fb0e5c0 100644
--- a/net/disk_cache/rankings.cc
+++ b/net/disk_cache/blockfile/rankings.cc
@@ -2,17 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "net/disk_cache/rankings.h"
+#include "net/disk_cache/blockfile/rankings.h"
 
 #include "base/metrics/histogram.h"
-#include "net/disk_cache/backend_impl.h"
-#include "net/disk_cache/disk_format.h"
-#include "net/disk_cache/entry_impl.h"
-#include "net/disk_cache/errors.h"
-#include "net/disk_cache/stress_support.h"
+#include "net/disk_cache/blockfile/backend_impl.h"
+#include "net/disk_cache/blockfile/disk_format.h"
+#include "net/disk_cache/blockfile/entry_impl.h"
+#include "net/disk_cache/blockfile/errors.h"
+#include "net/disk_cache/blockfile/stress_support.h"
 
 #define CACHE_HISTOGRAM_MACROS_BACKEND_IMPL_OBJ backend_
-#include "net/disk_cache/histogram_macros.h"
+#include "net/disk_cache/blockfile/histogram_macros.h"
 
 using base::Time;
 using base::TimeTicks;