Remove UserAgent ShadowRoot + Author ShadowRoot code.

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 294 matching lines @@
     case UseCounter::EncryptedMediaInsecureOrigin:
         return "requestMediaKeySystemAccess() is deprecated on insecure origins in the specification. Support will be removed in the future. You should consider switching your application to a secure origin, such as HTTPS. See https://goo.gl/rStTGz for more details.";
 
     case UseCounter::ApplicationCacheManifestSelectInsecureOrigin:
     case UseCounter::ApplicationCacheAPIInsecureOrigin:
         return "Use of the Application Cache is deprecated on insecure origins. Support will be removed in the future. You should consider switching your application to a secure origin, such as HTTPS. See https://goo.gl/rStTGz for more details.";
 
     case UseCounter::ElementCreateShadowRootMultiple:
         return "Calling Element.createShadowRoot() for an element which already hosts a shadow root is deprecated. See https://www.chromestatus.com/features/4668884095336448 for more details.";
 
-    case UseCounter::ElementCreateShadowRootMultipleWithUserAgentShadowRoot:
-        return "Calling Element.createShadowRoot() for an element which already hosts a user-agent shadow root is deprecated. See https://www.chromestatus.com/features/4668884095336448 for more details.";
-
     case UseCounter::CSSDeepCombinator:
         return "/deep/ combinator is deprecated. See https://www.chromestatus.com/features/6750456638341120 for more details.";
 
     case UseCounter::CSSSelectorPseudoShadow:
         return "::shadow pseudo-element is deprecated. See https://www.chromestatus.com/features/6750456638341120 for more details.";
 
     case UseCounter::SVGSMILElementInDocument:
     case UseCounter::SVGSMILAnimationInImageRegardlessOfCache:
         return "SVG's SMIL animations (<animate>, <set>, etc.) are deprecated and will be removed. Please use CSS animations or Web animations instead.";
 
@@ skipping 39 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));
 
     // Features that aren't deprecated don't have a deprecation message.
     default:
         return String();
     }
 }
 
 } // namespace blink