[ios] EarlGrey tests for HTTP Authentication.

ios/chrome/test/earl_grey/chrome_matchers.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 "ios/chrome/test/earl_grey/chrome_matchers.h"
 
 #import <OCHamcrest/OCHamcrest.h>
 
 #import <WebKit/WebKit.h>
 
@@ skipping 146 matching lines @@
   };
 
   return grey_allOf(
       webViewWithNavDelegateOfClass([StaticHtmlViewController class]),
       [[[GREYElementMatcherBlock alloc] initWithMatchesBlock:matches
                                             descriptionBlock:describe]
           autorelease],
       nil);
 }
 
+id<GREYMatcher> cancelButton() {
+  return buttonWithAccessibilityLabelId(IDS_CANCEL);
+}
+
 id<GREYMatcher> forwardButton() {
   return buttonWithAccessibilityLabelId(IDS_ACCNAME_FORWARD);
 }
 
 id<GREYMatcher> backButton() {
   return buttonWithAccessibilityLabelId(IDS_ACCNAME_BACK);
 }
 
 id<GREYMatcher> reloadButton() {
   return buttonWithAccessibilityLabelId(IDS_IOS_ACCNAME_RELOAD);
@@ skipping 31 matching lines @@
 }
 
 id<GREYMatcher> collectionViewSwitchCell(NSString* accessibilityIdentifier,
                                          BOOL isOn) {
   return grey_allOf(grey_accessibilityID(accessibilityIdentifier),
                     collectionViewSwitchIsOn(isOn), grey_sufficientlyVisible(),
                     nil);
 }
 
 }  // namespace chrome_test_util