Reorganize net/disk_cache into backend specific directories.

net/disk_cache/memory/mem_backend_impl.h

Index: net/disk_cache/memory/mem_backend_impl.h
diff --git a/net/disk_cache/mem_backend_impl.h b/net/disk_cache/memory/mem_backend_impl.h
similarity index 95%
rename from net/disk_cache/mem_backend_impl.h
rename to net/disk_cache/memory/mem_backend_impl.h
index 8da39cc7f2607e922bd2e2d8a3998b54d91fb951..5f31be54da9e4abb29087e91669316fa2b4f1241 100644
--- a/net/disk_cache/mem_backend_impl.h
+++ b/net/disk_cache/memory/mem_backend_impl.h
@@ -4,13 +4,13 @@
 
 // See net/disk_cache/disk_cache.h for the public interface of the cache.
 
-#ifndef NET_DISK_CACHE_MEM_BACKEND_IMPL_H__
-#define NET_DISK_CACHE_MEM_BACKEND_IMPL_H__
+#ifndef NET_DISK_CACHE_MEMORY_MEM_BACKEND_IMPL_H_
+#define NET_DISK_CACHE_MEMORY_MEM_BACKEND_IMPL_H_
 
 #include "base/compiler_specific.h"
 #include "base/containers/hash_tables.h"
 #include "net/disk_cache/disk_cache.h"
-#include "net/disk_cache/mem_rankings.h"
+#include "net/disk_cache/memory/mem_rankings.h"
 
 namespace net {
 class NetLog;
@@ -117,4 +117,4 @@ class NET_EXPORT_PRIVATE MemBackendImpl : public Backend {
 
 }  // namespace disk_cache
 
-#endif  // NET_DISK_CACHE_MEM_BACKEND_IMPL_H__
+#endif  // NET_DISK_CACHE_MEMORY_MEM_BACKEND_IMPL_H_