Update the deprecation message of /deep/ and remove that of ::shadow

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 331 matching lines @@
           "details.",
           milestoneString(M61));
 
     case UseCounter::kElementCreateShadowRootMultiple:
       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::kCSSDeepCombinator:
-      return String::Format(
-          "/deep/ combinator is deprecated and will be a no-op in %s. See "
-          "https://www.chromestatus.com/features/4964279606312960 for more "
-          "details.",
-          milestoneString(M60));
-
-    case UseCounter::kCSSSelectorPseudoShadow:
-      return willBeRemoved("::shadow pseudo-element", M60, "6750456638341120");
+      return "/deep/ combinator is no longer supported in CSS dynamic profile. "
+             "It is now effectively no-op, acting as if it were a descendant "
+             "combinator. You should consider to remove it. See "
+             "https://www.chromestatus.com/features/4964279606312960 for more "
+             "details.";
 
     case UseCounter::kVREyeParametersOffset:
       return replacedBy("VREyeParameters.offset",
                         "view matrices provided by VRFrameData");
 
     case UseCounter::kCSSSelectorInternalMediaControlsOverlayCastButton:
       return willBeRemoved(
           "-internal-media-controls-overlay-cast-button selector", M61,
           "5714245488476160");
 
@@ skipping 44 matching lines @@
       return willBeRemoved("SVGPathElement.getPathSegAtLength", M62,
                            "5638783282184192");
 
     // Features that aren't deprecated don't have a deprecation message.
     default:
       return String();
   }
 }
 
 }  // namespace blink