Deprecate step timing with position 'middle'

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/LocalFrame.h"
@@ skipping 422 matching lines @@
           "\"mastercard\", \"mir\", \"unionpay\", \"visa\") as payment method",
           "payment method name \"basic-card\" with issuer network in the "
           "\"supportedNetworks\" field",
           M64, "5725727580225536");
     case WebFeature::kCredentialManagerRequireUserMediation:
       return replacedWillBeRemoved(
           "The CredentialsContainer.requireUserMediation method",
           "the CredentialsContainer.preventSilentAccess method", M62,
           "4781762488041472");
 
+    case WebFeature::kDeprecatedTimingFunctionStepMiddle:
+      return replacedWillBeRemoved(
+          "The step timing function with step position 'middle'",
+          "the frames timing function", M62, "5189363944128512");
+
     // Features that aren't deprecated don't have a deprecation message.
     default:
       return String();
   }
 }
 
 }  // namespace blink