Make experimental NS API not purely virtual

Because not all subclasses will want to bother overriding these methods.

R=bjornv@webrtc.org, kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/18689004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6592 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/audio_processing/include/mock_audio_processing.h

@@ -186,10 +186,6 @@ class MockAudioProcessing : public AudioProcessing {
           ChannelLayout reverse_layout));
   MOCK_METHOD1(SetExtraOptions,
       void(const Config& config));
-  MOCK_METHOD1(EnableExperimentalNs,
-      int(bool enable));
-  MOCK_CONST_METHOD0(experimental_ns_enabled,
-      bool());
   MOCK_METHOD1(set_sample_rate_hz,
       int(int rate));
   MOCK_CONST_METHOD0(input_sample_rate_hz,