net: Cleanup class/struct forward declarations

net/cert/x509_util.h

Index: net/cert/x509_util.h
diff --git a/net/cert/x509_util.h b/net/cert/x509_util.h
index 07f4e21b1d32d42ca964d476eaf0eb88bc7d675e..e29219d3ecaaad84e0fafc8fcd470e15b06b9d98 100644
--- a/net/cert/x509_util.h
+++ b/net/cert/x509_util.h
@@ -17,7 +17,6 @@
 #include "net/base/net_export.h"
 
 namespace crypto {
-class ECPrivateKey;
 class RSAPrivateKey;
 }