--- a/dom/media/eme/MediaKeySystemAccess.cpp
+++ b/dom/media/eme/MediaKeySystemAccess.cpp
@@ -45,23 +45,28 @@ NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(Me
                                       mParent)
 NS_IMPL_CYCLE_COLLECTING_ADDREF(MediaKeySystemAccess)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(MediaKeySystemAccess)
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(MediaKeySystemAccess)
   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
   NS_INTERFACE_MAP_ENTRY(nsISupports)
 NS_INTERFACE_MAP_END
 
+static nsCString
+ToCString(const MediaKeySystemConfiguration& aConfig);
+
 MediaKeySystemAccess::MediaKeySystemAccess(nsPIDOMWindowInner* aParent,
                                            const nsAString& aKeySystem,
                                            const MediaKeySystemConfiguration& aConfig)
   : mParent(aParent)
   , mKeySystem(aKeySystem)
   , mConfig(aConfig)
 {
+  EME_LOG("Created MediaKeySystemAccess for keysystem=%s config=%s",
+          NS_ConvertUTF16toUTF8(mKeySystem).get(), mozilla::dom::ToCString(mConfig).get());
 }
 
 MediaKeySystemAccess::~MediaKeySystemAccess()
 {
 }
 
 JSObject*
 MediaKeySystemAccess::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)