Reorganize net/disk_cache into backend specific directories.

net/disk_cache/memory/mem_entry_impl.cc

Index: net/disk_cache/memory/mem_entry_impl.cc
diff --git a/net/disk_cache/mem_entry_impl.cc b/net/disk_cache/memory/mem_entry_impl.cc
similarity index 99%
rename from net/disk_cache/mem_entry_impl.cc
rename to net/disk_cache/memory/mem_entry_impl.cc
index 7d0095898b4fe75d059d881d231157a2d9940379..0b6d858c128c85e87fdcf4406b652496c7a5f2fc 100644
--- a/net/disk_cache/mem_entry_impl.cc
+++ b/net/disk_cache/memory/mem_entry_impl.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "net/disk_cache/mem_entry_impl.h"
+#include "net/disk_cache/memory/mem_entry_impl.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ -10,7 +10,7 @@
 #include "base/values.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
-#include "net/disk_cache/mem_backend_impl.h"
+#include "net/disk_cache/memory/mem_backend_impl.h"
 #include "net/disk_cache/net_log_parameters.h"
 
 using base::Time;