mash: Move ash_switches.* to ash/common; cleanup DEPS.

ash/display/display_layout_store.cc

 // Copyright 2013 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 <stdio.h>
 
-#include "ash/ash_switches.h"
+#include "ash/common/ash_switches.h"
 #include "ash/display/display_layout_store.h"
 #include "ash/display/display_manager.h"
 #include "ash/display/display_util.h"
 #include "ash/shell.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "ui/display/display.h"
 
 namespace ash {
 
@@ skipping 95 matching lines @@
     placement.display_id = list[i + 1];
     placement.parent_display_id = list[i];
     layout->placement_list.push_back(placement);
   }
   layouts_[list] = std::move(layout);
   auto iter = layouts_.find(list);
   return iter->second.get();
 }
 
 }  // namespace ash