net: remove CryptoModule class

https://codereview.chromium.org/2724013002

chromium_src/chrome/browser/certificate_manager_model.cc

@@ -14,7 +14,6 @@
 #include "content/public/browser/resource_context.h"
 #include "crypto/nss_util.h"
 #include "crypto/nss_util_internal.h"
-#include "net/base/crypto_module.h"
 #include "net/base/net_errors.h"
 #include "net/cert/nss_cert_database.h"
 #include "net/cert/x509_certificate.h"