Adding googAudioNetworkAdaptorConfig to MediaConstraintsInterface.

webrtc/api/mediaconstraintsinterface.cc

Index: webrtc/api/mediaconstraintsinterface.cc
diff --git a/webrtc/api/mediaconstraintsinterface.cc b/webrtc/api/mediaconstraintsinterface.cc
index 14a92c22edb5fd17e90d9d70d13f10881fc0be2b..e35c067acc06624525c1ce2dcd67cab4bff1e5f8 100644
--- a/webrtc/api/mediaconstraintsinterface.cc
+++ b/webrtc/api/mediaconstraintsinterface.cc
@@ -56,6 +56,8 @@ const char MediaConstraintsInterface::kHighpassFilter[] =
 const char MediaConstraintsInterface::kTypingNoiseDetection[] =
     "googTypingNoiseDetection";
 const char MediaConstraintsInterface::kAudioMirroring[] = "googAudioMirroring";
+const char MediaConstraintsInterface::kAudioNetworkAdaptorConfig[] =
+    "googAudioNetworkAdaptorConfig";
 
 // Google-specific constraint keys for a local video source (getUserMedia).
 const char MediaConstraintsInterface::kNoiseReduction[] = "googNoiseReduction";