Change how background noise mode in NetEq is set

This change prepares for switching default background noise (bgn) mode
from on to off. The actual switch will be done later.

In this change, the bgn mode is included as a setting in NetEq's config
struct. We're also removing the connection between playout modes and
bgn modes in ACM. In practice this means that bgn mode will change from
off to on for streaming mode, but since the playout modes are not used
it does not matter.

BUG=3519
R=tina.legrand@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/21749004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6843 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/neteq/interface/neteq.h b/webrtc/modules/audio_coding/neteq/interface/neteq.h
index c67ab12..fdd000a 100644
--- a/webrtc/modules/audio_coding/neteq/interface/neteq.h
+++ b/webrtc/modules/audio_coding/neteq/interface/neteq.h
@@ -58,27 +58,29 @@
   kPlayoutStreaming
 };
 
-enum NetEqBackgroundNoiseMode {
-  kBgnOn,    // Default behavior with eternal noise.
-  kBgnFade,  // Noise fades to zero after some time.
-  kBgnOff    // Background noise is always zero.
-};
-
 // This is the interface class for NetEq.
 class NetEq {
  public:
+  enum BackgroundNoiseMode {
+    kBgnOn,    // Default behavior with eternal noise.
+    kBgnFade,  // Noise fades to zero after some time.
+    kBgnOff    // Background noise is always zero.
+  };
+
   struct Config {
     Config()
         : sample_rate_hz(16000),
           enable_audio_classifier(false),
           max_packets_in_buffer(50),
           // |max_delay_ms| has the same effect as calling SetMaximumDelay().
-          max_delay_ms(2000) {}
+          max_delay_ms(2000),
+          background_noise_mode(kBgnOn) {}
 
     int sample_rate_hz;  // Initial vale. Will change with input data.
     bool enable_audio_classifier;
     int max_packets_in_buffer;
     int max_delay_ms;
+    BackgroundNoiseMode background_noise_mode;
   };
 
   enum ReturnCodes {
@@ -259,12 +261,6 @@
   virtual int DecodedRtpInfo(int* sequence_number,
                              uint32_t* timestamp) const = 0;
 
-  // Sets the background noise mode.
-  virtual void SetBackgroundNoiseMode(NetEqBackgroundNoiseMode mode) = 0;
-
-  // Gets the background noise mode.
-  virtual NetEqBackgroundNoiseMode BackgroundNoiseMode() const = 0;
-
  protected:
   NetEq() {}