Add an error page for HTTP 404 error pages without bodies.

chrome/browser/extensions/api/web_navigation/web_navigation_apitest.cc

Index: chrome/browser/extensions/api/web_navigation/web_navigation_apitest.cc
diff --git a/chrome/browser/extensions/api/web_navigation/web_navigation_apitest.cc b/chrome/browser/extensions/api/web_navigation/web_navigation_apitest.cc
index 6654a0e00d6d8e5df8c2df47e88a12b296546ca7..0ebeb692eb59b5c3529f0fb9de61128a81265b5d 100644
--- a/chrome/browser/extensions/api/web_navigation/web_navigation_apitest.cc
+++ b/chrome/browser/extensions/api/web_navigation/web_navigation_apitest.cc
@@ -330,11 +330,26 @@ class TestResourceDispatcherHostDelegate
   DISALLOW_COPY_AND_ASSIGN(TestResourceDispatcherHostDelegate);
 };
 
+// Handles requests for URLs with paths of "/test*" sent to the test server, so
+// tests request a URL that receives a non-error response.
+std::unqiue_ptr<net::test_server::HttpResponse> HandleTestRequest(
+    const net::test_server::HttpRequest& request) {
+  if (!base::StartsWithASCII(request.relative_url, "/test"))
+    return nullptr;
+  std::unique_ptr<net::test_server::BasicHttpResponse> response(
+      new net::test_server::BasicHttpResponse());
+  response->set_content("This space intentionally left blank.");
+  return std::move(response);
+}
+
 }  // namespace
 
 class WebNavigationApiTest : public ExtensionApiTest {
  public:
-  WebNavigationApiTest() {}
+  WebNavigationApiTest() {
+    embedded_test_server()->RegisterRequestHandler(
+        base::Bind(&HandleTestRequest));
+  }
   ~WebNavigationApiTest() override {}
 
   void SetUpInProcessBrowserTestFixture() override {