Create ChromeEarlGrey waitForWebViewContainingText.

ios/chrome/browser/autofill/form_input_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 "base/strings/sys_string_conversions.h"
 #import "base/test/ios/wait_util.h"
 #include "ios/chrome/browser/autofill/form_input_accessory_view_controller.h"
 #include "ios/chrome/browser/ui/ui_util.h"
@@ skipping 69 matching lines @@
   // the left and right of the QuickType suggestions).
   if (IsIPadIdiom()) {
     EARL_GREY_TEST_SKIPPED(@"Skipped for iPad (no hidden toolbar in tablet)");
   }
 
   web::test::SetUpFileBasedHttpServer();
   GURL URL = web::test::HttpServer::MakeUrl(
       "http://ios/testing/data/http_server_files/multi_field_form.html");
   [ChromeEarlGrey loadURL:URL];
 
-  id<GREYMatcher> webViewMatcher =
-      chrome_test_util::WebViewContainingText("hello!");
-  [[EarlGrey selectElementWithMatcher:webViewMatcher]
-      assertWithMatcher:grey_notNil()];
+  [ChromeEarlGrey waitForWebViewContainingText:"hello!"];
 
   // Opening the keyboard from a webview blocks EarlGrey's synchronization.
   [[GREYConfiguration sharedInstance]
           setValue:@NO
       forConfigKey:kGREYConfigKeySynchronizationEnabled];
 
   // Brings up the keyboard by tapping on one of the form's field.
   [[EarlGrey
       selectElementWithMatcher:web::WebViewInWebState(
                                    chrome_test_util::GetCurrentWebState())]
@@ skipping 51 matching lines @@
 // visible doesn't crash the browser.
 - (void)testCloseKeyboardWhenNotVisible {
   FormInputAccessoryViewController* inputAccessoryViewController =
       chrome_test_util::GetInputAccessoryViewController();
   GREYAssertNotNil(inputAccessoryViewController,
                    @"The tab's input accessory view should not be non nil.");
   [inputAccessoryViewController closeKeyboardWithoutButtonPress];
 }
 
 @end