Move EarlGrey helper to check toolbar visibility into ChromeEarlGreyUI.

ios/chrome/test/earl_grey/chrome_earl_grey_ui.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_earl_grey_ui.h"
 
 #include "ios/chrome/browser/ui/tools_menu/tools_menu_constants.h"
 #import "ios/chrome/browser/ui/uikit_ui_util.h"
 #import "ios/chrome/test/app/chrome_test_util.h"
 #include "ios/chrome/test/app/navigation_test_util.h"
@@ skipping 61 matching lines @@
 }
 
 + (void)openShareMenu {
   if (IsCompact()) {
     [ChromeEarlGreyUI openToolsMenu];
   }
   [[EarlGrey selectElementWithMatcher:chrome_test_util::ShareButton()]
       performAction:grey_tap()];
 }
 
++ (void)waitForToolbarVisible:(BOOL)isVisible {
+  const NSTimeInterval kWaitForToolbarAnimationTimeout = 1.0;
+  ConditionBlock condition = ^{
+    NSError* error = nil;
+    id<GREYMatcher> visibleMatcher = isVisible ? grey_notNil() : grey_nil();
+    [[EarlGrey selectElementWithMatcher:chrome_test_util::ToolsMenuButton()]
+        assertWithMatcher:visibleMatcher
+                    error:&error];
+    return error == nil;
+  };
+  NSString* errorMessage =
+      isVisible ? @"Toolbar was not visible" : @"Toolbar was visible";
+  GREYAssert(testing::WaitUntilConditionOrTimeout(
+                 kWaitForToolbarAnimationTimeout, condition),
+             errorMessage);
+}
+
 @end