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

ash/common/ash_switches.h

Index: ash/common/ash_switches.h
diff --git a/ash/ash_switches.h b/ash/common/ash_switches.h
similarity index 95%
rename from ash/ash_switches.h
rename to ash/common/ash_switches.h
index ad89838d836072c299f800e2b8461455a781b458..d798e3e57584c81d02dde2cb8a5b66d78af19b8a 100644
--- a/ash/ash_switches.h
+++ b/ash/common/ash_switches.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef ASH_ASH_SWITCHES_H_
-#define ASH_ASH_SWITCHES_H_
+#ifndef ASH_COMMON_ASH_SWITCHES_H_
+#define ASH_COMMON_ASH_SWITCHES_H_
 
 #include "ash/ash_export.h"
 
@@ -60,4 +60,4 @@ ASH_EXPORT bool ConstrainPointerToRoot();
 }  // namespace switches
 }  // namespace ash
 
-#endif  // ASH_ASH_SWITCHES_H_
+#endif  // ASH_COMMON_ASH_SWITCHES_H_