Adds notification on passphrase type change

Now we have notifications for all sync service crypto state changes
except changes of passphrase type.

This CL makes all things the same.

Change-Id: Idd9cf978f9bfb6b8a45ac1891b815d42af834890
Reviewed-on: https://chromium-review.googlesource.com/1109968Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Commit-Queue: Aleksei Loshkarev <lixan@yandex-team.ru>
Cr-Commit-Position: refs/heads/master@{#569564}

components/sync/driver/sync_service_crypto.cc

@@ -344,6 +344,7 @@ void SyncServiceCrypto::OnPassphraseTypeChanged(PassphraseType type,
   DVLOG(1) << "Passphrase type changed to " << PassphraseTypeToString(type);
   cached_passphrase_type_ = type;
   cached_explicit_passphrase_time_ = passphrase_time;
+  notify_observers_.Run();
 }
 
 void SyncServiceCrypto::OnLocalSetPassphraseEncryption(