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 355 matching lines @@
 
     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::During_Microtask_SyncXHR:
         return willBeRemoved("Invoking 'send()' on a sync XHR during microtask execution", 54, "5647113010544640");
 
     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:
         return willBeRemoved("MIDIMessageEvent.receivedTime", 56, "5665772797952000");
 
     case UseCounter::V8SVGSVGElement_UseCurrentView_AttributeGetter:
         return willBeRemoved("SVGSVGElement.useCurrentView", 56, "4511711998509056");
 
     case UseCounter::V8SVGSVGElement_CurrentView_AttributeGetter:
         return willBeRemoved("SVGSVGElement.currentView", 56, "4511711998509056");
 
     // Features that aren't deprecated don't have a deprecation message.
     default:
         return String();
     }
 }
 
 } // namespace blink