Disable navigations in the unload handler.

third_party/WebKit/Source/core/frame/Deprecation.cpp

 // 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.
 
 #include "core/frame/Deprecation.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/frame/FrameConsole.h"
 #include "core/frame/FrameHost.h"
@@ skipping 342 matching lines @@
 
     case UseCounter::WindowPostMessageWithLegacyTargetOriginArgument:
         return replacedWillBeRemoved("'window.postMessage(message, transferables, targetOrigin)'", "'window.postMessage(message, targetOrigin, transferables)'", 54, "5719033043222528");
 
     case UseCounter::EncryptedMediaAllSelectedContentTypesMissingCodecs:
         return String::format("EME requires that contentType strings accepted by requestMediaKeySystemAccess() include codecs. Non-standard support for contentType strings without codecs will be removed in %s. Please specify the desired codec(s) as part of the contentType.", milestoneString(54));
 
     case UseCounter::UntrustedEventDefaultHandled:
         return String::format("A DOM event generated from JavaScript has triggered a default action inside the browser. This behavior is non-standard and will be removed in %s. See https://www.chromestatus.com/features/5718803933560832 for more details.", milestoneString(53));
 
-    case UseCounter::UnloadHandler_Navigation:
-        return "Navigating in the unload handler is deprecated and will be removed.";
-
     case UseCounter::TouchStartUserGestureUtilized:
         return willBeRemoved("Performing operations that require explicit user interaction on touchstart events", 54, "5649871251963904");
 
     case UseCounter::TouchMoveUserGestureUtilized:
         return willBeRemoved("Performing operations that require explicit user interaction on touchmove events", 54, "5649871251963904");
 
     case UseCounter::TouchEndDuringScrollUserGestureUtilized:
         return willBeRemoved("Performing operations that require explicit user interaction on touchend events that occur as part of a scroll", 54, "5649871251963904");
 
     case UseCounter::MIDIMessageEventReceivedTime:
@@ skipping 11 matching lines @@
     case UseCounter::NavigatorPointerEnabled:
         return "Navigator.pointerEnabled is a non-standard API added for experiments only. It will be removed in near future.";
 
     // Features that aren't deprecated don't have a deprecation message.
     default:
         return String();
     }
 }
 
 } // namespace blink