[webcrypto] Add RSA key generation using NSS.

content/renderer/webcrypto/webcrypto_impl_openssl.cc

Index: content/renderer/webcrypto/webcrypto_impl_openssl.cc
diff --git a/content/renderer/webcrypto/webcrypto_impl_openssl.cc b/content/renderer/webcrypto/webcrypto_impl_openssl.cc
index 83ae45c20e400460fd4a4dc12d6c581d37b5f6c9..23f89c2e04b2d9cebe53dc5c3aa46eee866cec1d 100644
--- a/content/renderer/webcrypto/webcrypto_impl_openssl.cc
+++ b/content/renderer/webcrypto/webcrypto_impl_openssl.cc
@@ -299,6 +299,17 @@ bool WebCryptoImpl::GenerateKeyInternal(
   return true;
 }
 
+bool WebCryptoImpl::GenerateKeyPairInternal(
+    const WebKit::WebCryptoAlgorithm& algorithm,
+    bool extractable,
+    WebKit::WebCryptoKeyUsageMask usage_mask,
+    WebKit::WebCryptoKey* public_key,
+    WebKit::WebCryptoKey* private_key) {
+  // TODO(padolph): Placeholder for OpenSSL implementation.
+  // Issue http://crbug.com/267888.
+  return false;
+}
+
 bool WebCryptoImpl::ImportKeyInternal(
     WebKit::WebCryptoKeyFormat format,
     const unsigned char* key_data,