Replace rtc::cricket::Settable with rtc::Maybe

talk/media/webrtc/webrtcvoiceengine.h

Index: talk/media/webrtc/webrtcvoiceengine.h
diff --git a/talk/media/webrtc/webrtcvoiceengine.h b/talk/media/webrtc/webrtcvoiceengine.h
index 1cf05e71a26a8bfefca3010aee1b66cc7bc860a7..d9caf085be034b4eeade84bc8d041b73d1cf5a82 100644
--- a/talk/media/webrtc/webrtcvoiceengine.h
+++ b/talk/media/webrtc/webrtcvoiceengine.h
@@ -171,9 +171,9 @@ class WebRtcVoiceEngine
   // values, and apply them in case they are missing in the audio options. We
   // need to do this because SetExtraOptions() will revert to defaults for
   // options which are not provided.
-  Settable<bool> extended_filter_aec_;
-  Settable<bool> delay_agnostic_aec_;
-  Settable<bool> experimental_ns_;
+  rtc::Maybe<bool> extended_filter_aec_;
+  rtc::Maybe<bool> delay_agnostic_aec_;
+  rtc::Maybe<bool> experimental_ns_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(WebRtcVoiceEngine);
 };