cros: Add app mode restrictions.

ash/shell_delegate.h

Index: ash/shell_delegate.h
diff --git a/ash/shell_delegate.h b/ash/shell_delegate.h
index cd7c10a74c3fc300e1ec26c7a7d5dc59c436c60e..8fbfeb32025d000c61cd8d38c7a818af50c0afd1 100644
--- a/ash/shell_delegate.h
+++ b/ash/shell_delegate.h
@@ -5,7 +5,7 @@
 #ifndef ASH_SHELL_DELEGATE_H_
 #define ASH_SHELL_DELEGATE_H_
 
-#include <vector>
+#include <string>
 
 #include "ash/ash_export.h"
 #include "ash/magnifier/magnifier_constants.h"
@@ -90,6 +90,9 @@ class ASH_EXPORT ShellDelegate {
   // restarted, typically due to logging in as a guest or logging out.
   virtual bool IsFirstRunAfterBoot() const = 0;
 
+  // Returns true if we're running in forced app mode.
+  virtual bool IsRunningInForcedAppMode() const = 0;
+
   // Returns true if a user is logged in whose session can be locked (i.e. the
   // user has a password with which to unlock the session).
   virtual bool CanLockScreen() const = 0;