Move all core files in //components/sessions into core/ subdir

components/sessions/core/session_backend_unittest.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
-#include "components/sessions/session_backend.h"
+#include "components/sessions/core/session_backend.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace sessions {
 namespace {
 
 typedef ScopedVector<sessions::SessionCommand> SessionCommands;
 
 struct TestData {
   sessions::SessionCommand::id_type command_id;
   std::string data;
@@ skipping 180 matching lines @@
   backend->ReadLastSessionCommandsImpl(&commands);
 
   // And make sure we get back the expected data.
   ASSERT_EQ(1U, commands.size());
   AssertCommandEqualsData(second_data, commands[0]);
 
   commands.clear();
 }
 
 }  // namespace sessions