Reorganize net/disk_cache into backend specific directories.

net/disk_cache/blockfile/backend_impl.h

Index: net/disk_cache/blockfile/backend_impl.h
diff --git a/net/disk_cache/backend_impl.h b/net/disk_cache/blockfile/backend_impl.h
similarity index 96%
rename from net/disk_cache/backend_impl.h
rename to net/disk_cache/blockfile/backend_impl.h
index 43e990f1544a88e9d30bef1c73ef3756a28b0101..3345258634751231dfbba14adeff7346ae5533c4 100644
--- a/net/disk_cache/backend_impl.h
+++ b/net/disk_cache/blockfile/backend_impl.h
@@ -4,20 +4,20 @@
 
 // See net/disk_cache/disk_cache.h for the public interface of the cache.
 
-#ifndef NET_DISK_CACHE_BACKEND_IMPL_H_
-#define NET_DISK_CACHE_BACKEND_IMPL_H_
+#ifndef NET_DISK_CACHE_BLOCKFILE_BACKEND_IMPL_H_
+#define NET_DISK_CACHE_BLOCKFILE_BACKEND_IMPL_H_
 
 #include "base/containers/hash_tables.h"
 #include "base/files/file_path.h"
 #include "base/timer/timer.h"
-#include "net/disk_cache/block_files.h"
+#include "net/disk_cache/blockfile/block_files.h"
+#include "net/disk_cache/blockfile/eviction.h"
+#include "net/disk_cache/blockfile/in_flight_backend_io.h"
+#include "net/disk_cache/blockfile/rankings.h"
+#include "net/disk_cache/blockfile/stats.h"
+#include "net/disk_cache/blockfile/stress_support.h"
+#include "net/disk_cache/blockfile/trace.h"
 #include "net/disk_cache/disk_cache.h"
-#include "net/disk_cache/eviction.h"
-#include "net/disk_cache/in_flight_backend_io.h"
-#include "net/disk_cache/rankings.h"
-#include "net/disk_cache/stats.h"
-#include "net/disk_cache/stress_support.h"
-#include "net/disk_cache/trace.h"
 
 namespace net {
 class NetLog;
@@ -397,4 +397,4 @@ class NET_EXPORT_PRIVATE BackendImpl : public Backend {
 
 }  // namespace disk_cache
 
-#endif  // NET_DISK_CACHE_BACKEND_IMPL_H_
+#endif  // NET_DISK_CACHE_BLOCKFILE_BACKEND_IMPL_H_