API add to set background noise mode.

Background noise mode.

BUG=
R=henrik.lundin@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2194005

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4835 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/neteq4/expand.cc b/webrtc/modules/audio_coding/neteq4/expand.cc
index 2d6dfb5..3d9fa38 100644
--- a/webrtc/modules/audio_coding/neteq4/expand.cc
+++ b/webrtc/modules/audio_coding/neteq4/expand.cc
@@ -294,8 +294,8 @@
 
       // Unmute the background noise.
       int16_t bgn_mute_factor = background_noise_->MuteFactor(channel_ix);
-      BackgroundNoise::BackgroundNoiseMode bgn_mode = background_noise_->mode();
-      if (bgn_mode == BackgroundNoise::kBgnFade &&
+      NetEqBackgroundNoiseMode bgn_mode = background_noise_->mode();
+      if (bgn_mode == kBgnFade &&
           consecutive_expands_ >= kMaxConsecutiveExpands &&
           bgn_mute_factor > 0) {
         // Fade BGN to zero.
@@ -317,8 +317,8 @@
       } else if (bgn_mute_factor < 16384) {
         // If mode is kBgnOff, or if kBgnFade has started fading,
         // Use regular |mute_slope|.
-        if (!stop_muting_ && bgn_mode != BackgroundNoise::kBgnOff &&
-            !(bgn_mode == BackgroundNoise::kBgnFade &&
+        if (!stop_muting_ && bgn_mode != kBgnOff &&
+            !(bgn_mode == kBgnFade &&
                 consecutive_expands_ >= kMaxConsecutiveExpands)) {
           DspHelper::UnmuteSignal(noise_vector, static_cast<int>(current_lag),
                                   &bgn_mute_factor, parameters.mute_slope,