Remove keyIdentifier.

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 346 matching lines @@
 
     case UseCounter::WebAnimationsEasingAsFunctionLinear:
         return String::format("Specifying animation easing as a function is deprecated and all support will be removed in %s, at which point this will throw a TypeError. This warning may have been triggered by the Web Animations or Polymer polyfills. See http://crbug.com/601672 for details.", milestoneString(54));
 
     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::V8KeyboardEvent_KeyIdentifier_AttributeGetter:
-        return willBeRemoved("'KeyboardEvent.keyIdentifier'", 54, "5316065118650368");
-
     case UseCounter::During_Microtask_SyncXHR:
         return willBeRemoved("Invoking 'send()' on a sync XHR during microtask execution", 54, "5647113010544640");
 
     case UseCounter::MediaStreamOnEnded:
         return willBeRemoved("The MediaStream 'ended' event", 54, "5730404371791872");
 
     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:
@@ skipping 11 matching lines @@
     case UseCounter::MIDIMessageEventReceivedTime:
         return willBeRemoved("MIDIMessageEvent.receivedTime", 56, "5665772797952000");
 
     // Features that aren't deprecated don't have a deprecation message.
     default:
         return String();
     }
 }
 
 } // namespace blink