Fix ErrorPageTestCase to not wait for a matcher with grey_nil()

ios/chrome/browser/ui/error_page_egtest.mm

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import <EarlGrey/EarlGrey.h>
 
 #include "components/strings/grit/components_strings.h"
 #import "ios/chrome/test/app/chrome_test_util.h"
 #include "ios/chrome/test/app/web_view_interaction_test_util.h"
 #import "ios/chrome/test/earl_grey/chrome_earl_grey.h"
 #import "ios/chrome/test/earl_grey/chrome_matchers.h"
 #import "ios/chrome/test/earl_grey/chrome_test_case.h"
 #import "ios/web/public/test/http_server.h"
 #import "ios/web/public/test/earl_grey/web_view_matchers.h"
 #include "ios/web/public/test/http_server_util.h"
 #include "ios/web/public/test/response_providers/data_response_provider.h"
 #include "ios/web/public/test/response_providers/error_page_response_provider.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 using chrome_test_util::OmniboxText;
 using chrome_test_util::TapWebViewElementWithId;
 using chrome_test_util::WebViewContainingText;
+using chrome_test_util::WebViewNotContainingText;
 
 using web::test::HttpServer;
 
 // Tests display of error pages for bad URLs.
 @interface ErrorPageTestCase : ChromeTestCase
 
 // Checks that the DNS error page is not visible.
 - (void)checkErrorPageIsNotVisible;
 
 @end
 
 @implementation ErrorPageTestCase
 
 #pragma mark - utilities
 
 - (void)checkErrorPageIsNotVisible {
   // Check that the webview belongs to the web controller, and that the error
   // text doesn't appear in the webview.
   id<GREYMatcher> webViewMatcher =
       web::WebViewInWebState(chrome_test_util::GetCurrentWebState());
   [[EarlGrey selectElementWithMatcher:webViewMatcher]
       assertWithMatcher:grey_notNil()];
   const std::string kError =
       l10n_util::GetStringUTF8(IDS_ERRORPAGES_HEADING_NOT_AVAILABLE);
-  [[EarlGrey selectElementWithMatcher:WebViewContainingText(kError)]
-      assertWithMatcher:grey_nil()];
+  [[EarlGrey selectElementWithMatcher:WebViewNotContainingText(kError)]
+      assertWithMatcher:grey_notNil()];
 }
 
 #pragma mark - tests
 
 // Tests whether the error page is displayed for a bad URL.
 - (void)testErrorPage {
   std::unique_ptr<web::DataResponseProvider> provider(
       new ErrorPageResponseProvider());
   web::test::SetUpHttpServer(std::move(provider));
 
@@ skipping 99 matching lines @@
   [ChromeEarlGrey loadURL:URL];
   TapWebViewElementWithId(kButtonId);
   // Check that the timer has completed.
   [[EarlGrey selectElementWithMatcher:WebViewContainingText(kTimerCompleted)]
       assertWithMatcher:grey_notNil()];
   // DNS error page should still not appear.
   [self checkErrorPageIsNotVisible];
 }
 
 @end