Remove ios/testing/earl_grey/wait_util.

ios/testing/earl_grey/wait_util.h

-// 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.
-
-#ifndef IOS_TESTING_EARL_GREY_WAIT_UTIL_H_
-#define IOS_TESTING_EARL_GREY_WAIT_UTIL_H_
-
-#import <Foundation/Foundation.h>
-
-namespace testing {
-
-// Waits until |condition| is true, or induces GREYAssert after |timeout|.
-void WaitUntilCondition(NSTimeInterval timeout, bool (^condition)(void));
-
-// Waits until |condition| is true, or induces GREYAssert after |timeout| with
-// |timeoutDescription| error message.
-void WaitUntilCondition(NSTimeInterval timeout,
-                        NSString* timeoutDescription,
-                        bool (^condition)(void));
-
-}  // namespace testing
-
-#endif  // IOS_TESTING_EARL_GREY_WAIT_UTIL_H_