Adding Deprecation Message for <keygen>

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 324 matching lines @@
 
     case UseCounter::RTCPeerConnectionCreateOfferLegacyNoFailureCallback:
         return "RTCPeerConnection.CreateOffer without a failure callback is deprecated. The failure callback will be a required parameter in M50. See https://www.chromestatus.com/feature/5663288008376320 for more details";
 
     case UseCounter::ObjectObserve:
         return willBeRemoved("'Object.observe'", 50, "6147094632988672");
 
     case UseCounter::SVGZoomEvent:
         return willBeRemoved("'SVGZoomEvent'", 52, "5760883808534528");
 
+    case UseCounter::HTMLKeygenElement:
+        return "The <keygen> element is deprecated and will be removed.";

[jochen (gone - plz use gerrit), 2016/02/23 15:23:30]

please use the willBeRemoved() method to construct the message

[svaldez, 2016/02/23 15:35:47]

The removal timeline is still slightly rough, though the hope is to remove in
54/55.

+
     // Features that aren't deprecated don't have a deprecation message.
     default:
         return String();
     }
 }
 
 } // namespace blink