[webcrypto] Disable RSA key import for NSS versions less than 3.16.2.

content/child/webcrypto/status.cc

Index: content/child/webcrypto/status.cc
diff --git a/content/child/webcrypto/status.cc b/content/child/webcrypto/status.cc
index 5ddbf39e14090a65c1198c1cac256c46be1feb8b..38f4d466f60a949b42f5d08fdf7618401dc78124 100644
--- a/content/child/webcrypto/status.cc
+++ b/content/child/webcrypto/status.cc
@@ -151,8 +151,11 @@ Status Status::ErrorDataTooSmall() {
 }
 
 Status Status::ErrorUnsupported() {
-  return Status(blink::WebCryptoErrorTypeNotSupported,
-                "The requested operation is unsupported");
+  return ErrorUnsupported("The requested operation is unsupported");
+}
+
+Status Status::ErrorUnsupported(const std::string message) {
+  return Status(blink::WebCryptoErrorTypeNotSupported, message);
 }
 
 Status Status::ErrorUnexpected() {