diff --git a/netwerk/protocol/http/src/PHttpChannelParams.h b/netwerk/protocol/http/src/PHttpChannelParams.h
index 4f9443b8336b..51f4561b6e0e 100644
--- a/netwerk/protocol/http/src/PHttpChannelParams.h
+++ b/netwerk/protocol/http/src/PHttpChannelParams.h
@@ -49,6 +49,9 @@
 #include "nsHttpHeaderArray.h"
 #include "nsHttpResponseHead.h"
 
+#include "nsIStringStream.h"
+#include "nsISupportsPrimitives.h"
+
 namespace mozilla {
 namespace net {
 
@@ -192,6 +195,53 @@ struct ParamTraits<nsHttpResponseHead>
   }
 };
 
+template<>
+struct ParamTraits<nsIStringInputStream*>
+{
+  typedef nsIStringInputStream* paramType;
+
+  static void Write(Message* aMsg, const paramType& aParam)
+  {
+    nsCAutoString value;
+    nsCOMPtr<nsISupportsCString> cstr(do_QueryInterface(aParam));
+
+    if (cstr) {
+      cstr->GetData(value);
+    } else {
+      PRUint32 length;
+      aParam->Available(&length);
+      value.SetLength(length);
+      NS_ASSERTION(value.Length() == length, "SetLength failed");
+      char *c = value.BeginWriting();
+      PRUint32 bytesRead;
+      nsresult rv = aParam->Read(c, length, &bytesRead);
+      NS_ASSERTION(NS_SUCCEEDED(rv) && bytesRead == length, "Read failed");
+    }
+
+    WriteParam(aMsg, value);
+  }
+
+  static bool Read(const Message* aMsg, void** aIter, paramType* aResult)
+  {
+    nsCAutoString value;
+    if (!ReadParam(aMsg, aIter, &value))
+      return false;
+
+    nsresult rv;
+
+    nsCOMPtr<nsIStringInputStream> stream
+      (do_CreateInstance("@mozilla.org/io/string-input-stream;1", &rv));
+    if (NS_FAILED(rv))
+      return false;
+
+    rv = stream->SetData(value.get(), value.Length());
+    if (NS_FAILED(rv))
+      return false;
+
+    stream.forget(aResult);
+    return true;
+  }
+};
 } // namespace IPC
 
 #endif // mozilla_net_PHttpChannelParams_h