Add the Sync.PassphraseType histogram.

sync/internal_api/public/sync_encryption_handler.h

 // Copyright 2012 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.
 
 #ifndef SYNC_INTERNAL_API_PUBLIC_SYNC_ENCRYPTION_HANDLER_H_
 #define SYNC_INTERNAL_API_PUBLIC_SYNC_ENCRYPTION_HANDLER_H_
 
 #include <string>
 
 #include "base/time/time.h"
@@ skipping 14 matching lines @@
   REASON_ENCRYPTION = 1,               // The cryptographer requires a
                                        // passphrase for its first attempt at
                                        // encryption. Happens only during
                                        // migration or upgrade.
   REASON_DECRYPTION = 2,               // The cryptographer requires a
                                        // passphrase for its first attempt at
                                        // decryption.
 };
 
 // The different states for the encryption passphrase. These control if and how
 // the user should be prompted for a decryption passphrase.

[Alexei Svitkine (slow), 2014/12/04 19:57:06]

Nit: Add a note not to re-order or delete entries, since these are used in a
histogram.

[maxbogue, 2014/12/04 21:14:24]

Done.

 enum PassphraseType {
   IMPLICIT_PASSPHRASE = 0,             // GAIA-based passphrase (deprecated).
   KEYSTORE_PASSPHRASE = 1,             // Keystore passphrase.
   FROZEN_IMPLICIT_PASSPHRASE = 2,      // Frozen GAIA passphrase.
   CUSTOM_PASSPHRASE = 3,               // User-provided passphrase.
 };
 
+const int PASSPHRASE_TYPE_SIZE = 4;

[Alexei Svitkine (slow), 2014/12/04 19:57:06]

Usually, this is put inside the enum at the end, so it automatically grows as
new entries are added.

If there's a good reason why you'd rather not do that, I'm ok with that. If not,
please follow the convention.

[maxbogue, 2014/12/04 21:14:24]

I thought about doing that, but it might affect code that depends on those being
the only possible values for that enum (thinking switch statements). Nicolas,
have any thoughts on this?

[Nicolas Zea, 2014/12/05 00:53:19]

I'm fine with adding a NUM_PASSPHRASE_TYPES enum, but not sure if you'll need to
update any switch statements.

[maxbogue, 2014/12/05 18:58:59]

Done. It all compiled.

+
 // Enum used to distinguish which bootstrap encryption token is being updated.
 enum BootstrapTokenType {
   PASSPHRASE_BOOTSTRAP_TOKEN,
   KEYSTORE_BOOTSTRAP_TOKEN
 };
 
 // Sync's encryption handler. Handles tracking encrypted types, ensuring the
 // cryptographer encrypts with the proper key and has the most recent keybag,
 // and keeps the nigori node up to date.
 // Implementations of this class must be assumed to be non-thread-safe. All
@@ skipping 115 matching lines @@
   // bag of encryption keys in the nigori node.
   virtual PassphraseType GetPassphraseType() const = 0;
 
   // The set of types that are always encrypted.
   static ModelTypeSet SensitiveTypes();
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_SYNC_ENCRYPTION_HANDLER_H_