Fix typo in documentation on url::Origin.unique

BUG=574883

Review URL: https://codereview.chromium.org/1565913002

Cr-Commit-Position: refs/heads/master@{#368156}
diff --git a/url/origin.h b/url/origin.h
index 3b9f50bd..73e6248 100644
--- a/url/origin.h
+++ b/url/origin.h
@@ -67,7 +67,7 @@
 //     origin.scheme(); // "https"
 //     origin.host(); // "example.com"
 //     origin.port(); // 443
-//     origin.IsUnique(); // false
+//     origin.unique(); // false
 //
 // * To answer the question "Are |this| and |that| "same-origin" with each
 //   other?", use |Origin::IsSameOriginWith|: