Send deprecation messages for prefixed gradients now that it's possible.

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 406 matching lines @@
           milestoneString(M60));
 
     case UseCounter::kV8RTCPeerConnection_GetStreamById_Method:
       return willBeRemoved("RTCPeerConnection.getStreamById()", M62,
                            "5751819573657600");
 
     case UseCounter::kV8SVGPathElement_GetPathSegAtLength_Method:
       return willBeRemoved("SVGPathElement.getPathSegAtLength", M62,
                            "5638783282184192");
 
+    case UseCounter::kDeprecatedWebKitLinearGradient:
+      return replacedBy("-webkit-linear-gradient", "linear-gradient");
+
+    case UseCounter::kDeprecatedWebKitRepeatingLinearGradient:
+      return replacedBy("-webkit-repeating-linear-gradient",
+                        "repeating-linear-gradient");
+
+    case UseCounter::kDeprecatedWebKitGradient:
+      return replacedBy("-webkit-gradient",
+                        "linear-gradient or radial-gradient");
+
+    case UseCounter::kDeprecatedWebKitRadialGradient:
+      return replacedBy("-webkit-radial-gradient", "radial-gradient");
+
+    case UseCounter::kDeprecatedWebKitRepeatingRadialGradient:
+      return replacedBy("-webkit-repeating-radial-gradient",
+                        "repeating-radial-gradient");
+
     // Features that aren't deprecated don't have a deprecation message.
     default:
       return String();
   }
 }
 
 }  // namespace blink