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 424 matching lines @@
           "The rtcpMuxPolicy option is being considered for "
           "removal and may be removed no earlier than %s. If you depend on it, "
           "please see https://www.chromestatus.com/features/5654810086866944 "
           "for more details.",
           milestoneString(M60));
 
     case UseCounter::V8IDBFactory_WebkitGetDatabaseNames_Method:
       return willBeRemoved("indexedDB.webkitGetDatabaseNames()", M60,
                            "5725741740195840");
 
+    case UseCounter::DeprecatedWebKitLinearGradient:
+      return replacedBy("-webkit-linear-gradient", "linear-gradient");
+
+    case UseCounter::DeprecatedWebKitRepeatingLinearGradient:
+      return replacedBy("-webkit-repeating-linear-gradient",
+                        "repeating-linear-gradient");
+
+    case UseCounter::DeprecatedWebKitGradient:
+      return replacedBy("-webkit-gradient",
+                        "linear-gradient or radial-gradient");
+
+    case UseCounter::DeprecatedWebKitRadialGradient:
+      return replacedBy("-webkit-radial-gradient", "radial-gradient");
+
+    case UseCounter::DeprecatedWebKitRepeatingRadialGradient:
+      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