Mark testContextMenuOpenInNewTabFromTallPage FLAKY.

ios/chrome/browser/context_menu/context_menu_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>
 #import <UIKit/UIKit.h>
 #import <XCTest/XCTest.h>
 
 #include "base/strings/sys_string_conversions.h"
 #include "ios/chrome/browser/ui/ui_util.h"
@@ skipping 171 matching lines @@
   // Verify url and tab count.
   [[EarlGrey selectElementWithMatcher:chrome_test_util::OmniboxText(
                                           destinationURL.GetContent())]
       assertWithMatcher:grey_notNil()];
   chrome_test_util::AssertMainTabCount(2U);
 }
 
 // Tests "Open in New Tab" on context menu  on a link that requires scrolling
 // on the page to verify that context menu can be properly triggered in the
 // current screen view.
-- (void)testContextMenuOpenInNewTabFromTallPage {
+// TODO(crbug.com/701104): This test is flaky because sometimes it doesn't
+// scroll down far enough for the link to be visible.
+- (void)FLAKY_testContextMenuOpenInNewTabFromTallPage {
   // Set up test simple http server.
   std::map<GURL, std::string> responses;
   GURL initialURL =
       web::test::HttpServer::MakeUrl("http://scenarioContextMenuOpenInNewTab");
   GURL destinationURL = web::test::HttpServer::MakeUrl("http://destination");
 
   // The initial page contains a link to the destination page that is below a
   // really tall div so that scrolling is required.
   responses[initialURL] =
       "<div style='height:4000px'></div>"
@@ skipping 43 matching lines @@
   SelectTabAtIndexInCurrentMode(1U);
 
   // Verify url and tab count.
   [[EarlGrey selectElementWithMatcher:chrome_test_util::OmniboxText(
                                           destinationURL.GetContent())]
       assertWithMatcher:grey_notNil()];
   chrome_test_util::AssertMainTabCount(2U);
 }
 
 @end