Check that usage isn't empty when generateKey() is called

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 5fca40c86c15037e08f1588c5ca70eb1d5342039..c74e815c2b91ea9d775e48fb01b00a3e30a9f537 100644
--- a/content/child/webcrypto/status.cc
+++ b/content/child/webcrypto/status.cc
@@ -268,6 +268,11 @@ Status Status::ErrorCreateKeyBadUsages() {
                 "Cannot create a key using the specified key usages.");
 }
 
+Status Status::ErrorCreateKeyEmptyUsages() {
+  return Status(blink::WebCryptoErrorTypeSyntax,
+                "Usages cannot be empty when creating a key.");
+}
+
 Status Status::ErrorImportedEcKeyIncorrectCurve() {
   return Status(
       blink::WebCryptoErrorTypeData,