cryptohome: Move Options definition to the interface class

Move struct Options definition from MountHelper class to
MountHelperInterface class since this struct will be used by
OutOfProcessHelper too.

BUG=chromium:1074735
TEST=tast run cryptohome.GuestSession passes.
TEST=unit tests pass.
TEST=cryptohome --action=mount_ex succeeds.

Change-Id: Iadb02910fa7a1f904c0b7ae6ee0cc001eb85e66b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/2314918
Commit-Queue: Betul Soysal <betuls@google.com>
Tested-by: Betul Soysal <betuls@google.com>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
diff --git a/cryptohome/mount_helper.h b/cryptohome/mount_helper.h
index 55647e5..c0dd030 100644
--- a/cryptohome/mount_helper.h
+++ b/cryptohome/mount_helper.h
@@ -38,6 +38,12 @@
  public:
   virtual ~MountHelperInterface() {}
 
+  struct Options {
+    MountType type = MountType::NONE;
+    bool to_migrate_from_ecryptfs = false;
+    bool shadow_only = false;
+  };
+
   // Ephemeral mounts cannot be performed twice, so cryptohome needs to be able
   // to check whether an ephemeral mount can be performed.
   virtual bool CanPerformEphemeralMount() const = 0;
@@ -75,12 +81,6 @@
         platform_(platform) {}
   ~MountHelper() = default;
 
-  struct Options {
-    MountType type = MountType::NONE;
-    bool to_migrate_from_ecryptfs = false;
-    bool shadow_only = false;
-  };
-
   // Returns the temporary user path while we're migrating for
   // http://crbug.com/224291.
   static base::FilePath GetNewUserPath(const std::string& username);