Remove all usage of -webkit-*gradient inside blink

Source/web/resources/pickerButton.css

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 input[type='button'],
 button {
     -webkit-appearance: none;
     -webkit-user-select: none;
-    background-image: -webkit-linear-gradient(#ededed, #ededed 38%, #dedede);
+    background-image: linear-gradient(#ededed, #ededed 38%, #dedede);
     border: 1px solid rgba(0, 0, 0, 0.25);
     border-radius: 2px;
     box-shadow: 0 1px 0 rgba(0, 0, 0, 0.08),
     inset 0 1px 2px rgba(255, 255, 255, 0.75);
     color: #444;
     font: inherit;
     text-shadow: 0 1px 0 rgb(240, 240, 240);
     min-height: 2em;
     min-width: 4em;
     -webkit-padding-end: 10px;
     -webkit-padding-start: 10px;
     margin: 0;
 }
 
 :enabled:hover:-webkit-any(button, input[type='button']) {
-    background-image: -webkit-linear-gradient(#f0f0f0, #f0f0f0 38%, #e0e0e0);
+    background-image: linear-gradient(#f0f0f0, #f0f0f0 38%, #e0e0e0);
     border-color: rgba(0, 0, 0, 0.3);
     box-shadow: 0 1px 0 rgba(0, 0, 0, 0.12), inset 0 1px 2px rgba(255, 255, 255, 0.95);
     color: black;
 }
 
 :enabled:active:-webkit-any(button, input[type='button']) {
-    background-image: -webkit-linear-gradient(#e7e7e7, #e7e7e7 38%, #d7d7d7);
+    background-image: linear-gradient(#e7e7e7, #e7e7e7 38%, #d7d7d7);
     box-shadow: none;
     text-shadow: none;
 }
 
 :disabled:-webkit-any(button, input[type='button']) {
-    background-image: -webkit-linear-gradient(#f1f1f1, #f1f1f1 38%, #e6e6e6);
+    background-image: linear-gradient(#f1f1f1, #f1f1f1 38%, #e6e6e6);
     border-color: rgba(80, 80, 80, 0.2);
     box-shadow: 0 1px 0 rgba(80, 80, 80, 0.08), inset 0 1px 2px rgba(255, 255, 255, 0.75);
     color: #aaa;
 }
 
 :enabled:focus:-webkit-any(button, input[type='button']) {
     transition: border-color 200ms;
     /* We use border color because it follows the border radius (unlike outline).
     * This is particularly noticeable on mac. */
     border-color: rgb(77, 144, 254);
     outline: none;
 }