mash: Migrate ShellDelegate ownership and access to WmShell.

ash/common/shell_delegate.h

Index: ash/common/shell_delegate.h
diff --git a/ash/shell_delegate.h b/ash/common/shell_delegate.h
similarity index 97%
rename from ash/shell_delegate.h
rename to ash/common/shell_delegate.h
index b8da2d511d5a8702c1809fdb8fac655faea207bb..bf4d000f2a41d73c4393fbd4eb90f2d526918800 100644
--- a/ash/shell_delegate.h
+++ b/ash/common/shell_delegate.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_SHELL_DELEGATE_H_
-#define ASH_SHELL_DELEGATE_H_
+#ifndef ASH_COMMON_SHELL_DELEGATE_H_
+#define ASH_COMMON_SHELL_DELEGATE_H_
 
 #include <memory>
 #include <string>
@@ -166,4 +166,4 @@ class ASH_EXPORT ShellDelegate {
 
 }  // namespace ash
 
-#endif  // ASH_SHELL_DELEGATE_H_
+#endif  // ASH_COMMON_SHELL_DELEGATE_H_