Feed audio constraints over to WebRtcLocalAudioTrack

content/renderer/media/rtc_media_constraints.h

Index: content/renderer/media/rtc_media_constraints.h
diff --git a/content/renderer/media/rtc_media_constraints.h b/content/renderer/media/rtc_media_constraints.h
index c39790e486b73f7a2b35686095dcdc4b38667a17..58f84864f221883426c8ca57b6408e4486a7448d 100644
--- a/content/renderer/media/rtc_media_constraints.h
+++ b/content/renderer/media/rtc_media_constraints.h
@@ -6,6 +6,7 @@
 #define CONTENT_RENDERER_MEDIA_RTC_MEDIA_CONSTRAINTS_H_
 
 #include "base/compiler_specific.h"
+#include "content/common/content_export.h"
 #include "third_party/libjingle/source/talk/app/webrtc/mediaconstraintsinterface.h"
 
 namespace WebKit {
@@ -17,14 +18,21 @@ namespace content {
 // RTCMediaConstraints acts as a glue layer between WebKits MediaConstraints and
 // libjingle webrtc::MediaConstraintsInterface.
 // Constraints are used by PeerConnection and getUserMedia API calls.
-class RTCMediaConstraints : public webrtc::MediaConstraintsInterface {
+class CONTENT_EXPORT RTCMediaConstraints
+    : public NON_EXPORTED_BASE(webrtc::MediaConstraintsInterface) {
  public:
+  RTCMediaConstraints();
   explicit RTCMediaConstraints(
       const WebKit::WebMediaConstraints& constraints);
   virtual ~RTCMediaConstraints();
   virtual const Constraints& GetMandatory() const OVERRIDE;
   virtual const Constraints& GetOptional() const OVERRIDE;
   void AddOptional(const std::string& key, const std::string& value);
+  // Adds a mandatory constraint, optionally overriding an existing one.
+  // If the constraint is already set and |override_if_exists| is false,
+  // the function will return false, otherwise true.
+  bool AddMandatory(const std::string& key, const std::string& value,
+                    bool override_if_exists);
 
  protected:
   Constraints mandatory_;