--- a/ipc/glue/IPCMessageUtils.h
+++ b/ipc/glue/IPCMessageUtils.h
@@ -9,16 +9,17 @@
 
 #include "base/process_util.h"
 #include "chrome/common/ipc_message_utils.h"
 
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/DebugOnly.h"
 #include "mozilla/dom/ipc/StructuredCloneData.h"
+#include "mozilla/EnumSet.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/net/WebSocketFrame.h"
 #include "mozilla/TimeStamp.h"
 #ifdef XP_WIN
 #include "mozilla/TimeStamp_windows.h"
 #endif
 #include "mozilla/TypeTraits.h"
 #include "mozilla/IntegerTypeTraits.h"
@@ -913,16 +914,37 @@ struct ParamTraits<mozilla::Maybe<T>>
       *result = mozilla::Some(mozilla::Move(tmp));
     } else {
       *result = mozilla::Nothing();
     }
     return true;
   }
 };
 
+template<typename T>
+struct ParamTraits<mozilla::EnumSet<T>>
+{
+  typedef mozilla::EnumSet<T> paramType;
+
+  static void Write(Message* msg, const paramType& param)
+  {
+    WriteParam(msg, param.serialize());
+  }
+
+  static bool Read(const Message* msg, PickleIterator* iter, paramType* result)
+  {
+    decltype(result->serialize()) tmp;
+    if (ReadParam(msg, iter, &tmp)) {
+      result->deserialize(tmp);
+      return true;
+    }
+    return false;
+  }
+};
+
 template<class... Ts>
 struct ParamTraits<mozilla::Variant<Ts...>>
 {
   typedef mozilla::Variant<Ts...> paramType;
   using Tag = typename mozilla::detail::VariantTag<Ts...>::Type;
 
   struct VariantWriter
   {