Change the media::PowerLineFrequency from an enum class to a proper class

content/common/media/media_param_traits.cc

Index: content/common/media/media_param_traits.cc
diff --git a/content/common/media/media_param_traits.cc b/content/common/media/media_param_traits.cc
index 19c3b87975badff70e7cce7c8eeb4aa5b63b443a..338ecdcf09ca8a498cf7e3d591f7b7c119522bf2 100644
--- a/content/common/media/media_param_traits.cc
+++ b/content/common/media/media_param_traits.cc
@@ -14,6 +14,7 @@
 
 using media::AudioParameters;
 using media::ChannelLayout;
+using media::PowerLineFrequency;
 using media::VideoCaptureFormat;
 
 namespace IPC {
@@ -55,6 +56,29 @@ void ParamTraits<AudioParameters>::Log(const AudioParameters& p,
   l->append(base::StringPrintf("<AudioParameters>"));
 }
 
+void ParamTraits<PowerLineFrequency>::Write(Message *m,
+                                            const PowerLineFrequency& p) {
+  WriteParam(m, p.get());
+}
+
+bool ParamTraits<PowerLineFrequency>::Read(const Message* m,
+                                        base::PickleIterator* iter,
+                                        PowerLineFrequency* r) {
+  int freq;
+  if(!ReadParam(m, iter, &freq))
+  {
+    return false;
+  }
+  *r = PowerLineFrequency(freq);
+  return r->valid();
+}
+
+void ParamTraits<PowerLineFrequency>::Log(const PowerLineFrequency& p,
+                                        std::string *l) {
+  l->append(base::StringPrintf("<PowerLineFrequency> %d",
+                                p.get()));
+}
+
 void ParamTraits<VideoCaptureFormat>::Write(Message* m,
                                             const VideoCaptureFormat& p) {
   WriteParam(m, p.frame_size);