SameSite: Implement 'Strict'/'Lax' attribute parsing.

net/url_request/url_request_unittest.cc

Index: net/url_request/url_request_unittest.cc
diff --git a/net/url_request/url_request_unittest.cc b/net/url_request/url_request_unittest.cc
index a2da83abff4de7c4cad88bdb779fb07513bb4c0a..fef773db63c9db0f2b2cdfa998de448ddfaec5a4 100644
--- a/net/url_request/url_request_unittest.cc
+++ b/net/url_request/url_request_unittest.cc
@@ -2664,7 +2664,7 @@ TEST_F(URLRequestTest, SameSiteCookiesEnabled) {
   {
     TestDelegate d;
     scoped_ptr<URLRequest> req(default_context_.CreateRequest(
-        test_server.GetURL("/set-cookie?SameSiteCookieToSet=1;SameSite"),
+        test_server.GetURL("/set-cookie?SameSiteCookieToSet=1;SameSite=Strict"),
         DEFAULT_PRIORITY, &d));
     req->Start();
     base::RunLoop().Run();