Add a Config class interface to AudioProcessing for passing options.

Pass the Config down to all AudioProcessing components.

Also add an EchoCancellationImplWrapper to optionally create different
EchoCancellationImpls.

BUG=2117
TBR=turaj@webrtc.org
TESTED=git try

Review URL: https://webrtc-codereview.appspot.com/1843004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4400 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/audio_processing/include/audio_processing.h

@@ -13,6 +13,7 @@
 
 #include <stddef.h>  // size_t
 
+#include "webrtc/common.h"
 #include "webrtc/modules/interface/module.h"
 #include "webrtc/typedefs.h"
 
@@ -132,6 +133,10 @@ class AudioProcessing : public Module {
   // existing values. Otherwise they are no-ops.
   virtual int Initialize() = 0;
 
+  // Pass down additional options which don't have explicit setters. This
+  // ensures the options are applied immediately.
+  virtual void SetExtraOptions(const Config& config) = 0;
+
   // Sets the sample |rate| in Hz for both the primary and reverse audio
   // streams. 8000, 16000 or 32000 Hz are permitted.
   virtual int set_sample_rate_hz(int rate) = 0;