Revert of [ios] Do not trigger context menu while scrolling.

ios/web/web_state/ui/crw_web_controller.mm

 // Copyright 2012 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/web/web_state/ui/crw_web_controller.h"
 
 #import <WebKit/WebKit.h>
 
 #import <objc/runtime.h>
 #include <stddef.h>
@@ skipping 4576 matching lines @@
     //
     // To override the context menu, this recognizer needs to react faster than
     // the 0.75s one. The below gesture recognizer is initialized with a
     // detection duration a little lower than that (see
     // kLongPressDurationSeconds). It also points the delegate to this class
     // that
     // allows simultaneously operate along with the other recognizers.
     _contextMenuRecognizer.reset([[UILongPressGestureRecognizer alloc]
         initWithTarget:self
                 action:@selector(showContextMenu:)]);
-    [_contextMenuRecognizer
-        requireGestureRecognizerToFail:self.webScrollView.panGestureRecognizer];
     [_contextMenuRecognizer setMinimumPressDuration:kLongPressDurationSeconds];
     [_contextMenuRecognizer setAllowableMovement:kLongPressMoveDeltaPixels];
     [_contextMenuRecognizer setDelegate:self];
     [_webView addGestureRecognizer:_contextMenuRecognizer];
     // Certain system gesture handlers are known to conflict with our context
     // menu handler, causing extra events to fire when the context menu is
     // active.
 
     // A number of solutions have been investigated. The lowest-risk solution
     // appears to be to recurse through the web controller's recognizers,
@@ skipping 1041 matching lines @@
   }
 
   return web::WEB_VIEW_DOCUMENT_TYPE_GENERIC;
 }
 
 - (NSString*)refererFromNavigationAction:(WKNavigationAction*)action {
   return [action.request valueForHTTPHeaderField:@"Referer"];
 }
 
 @end