Add capability to simple http server to bound Set-Cookie to URLs.

ios/web/public/test/response_providers/response_provider.mm

Index: ios/web/public/test/response_providers/response_provider.mm
diff --git a/ios/web/public/test/response_providers/response_provider.mm b/ios/web/public/test/response_providers/response_provider.mm
index 00436cd6ba80861d4c6eebce08c0f35bda2188d5..22752a039c7ed2d50e2f9b6c39fd397ba4739981 100644
--- a/ios/web/public/test/response_providers/response_provider.mm
+++ b/ios/web/public/test/response_providers/response_provider.mm
@@ -50,11 +50,20 @@
 }
 
 // static
-scoped_refptr<net::HttpResponseHeaders>
-ResponseProvider::GetDefaultResponseHeaders(const std::string& cookie) {
-  scoped_refptr<net::HttpResponseHeaders> result = GetDefaultResponseHeaders();
-  result->AddCookie(cookie);
-  return result;
+std::map<GURL, scoped_refptr<net::HttpResponseHeaders>>
+ResponseProvider::GetDefaultResponseHeaders(
+    const std::map<GURL, std::pair<std::string, std::string>>& responses) {
+  std::map<GURL, scoped_refptr<net::HttpResponseHeaders>> headers;
+  for (const auto& pair : responses) {
+    std::string cookie = pair.second.first;
+    scoped_refptr<net::HttpResponseHeaders> result =
+        GetDefaultResponseHeaders();
+    if (!cookie.empty()) {
+      result->AddCookie(cookie);
+    }
+    headers.insert(std::make_pair(pair.first, result));
+  }
+  return headers;
 }
 
 // static