Remove all usage of -webkit-*gradient inside blink

Source/web/resources/pickerButton.css

Index: Source/web/resources/pickerButton.css
diff --git a/Source/web/resources/pickerButton.css b/Source/web/resources/pickerButton.css
index b207a0da95c72c027c9af73462aa2de3f524e9dd..ea82a51e3ccb30e968bea2259780955473b15258 100644
--- a/Source/web/resources/pickerButton.css
+++ b/Source/web/resources/pickerButton.css
@@ -26,7 +26,7 @@ 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),
@@ -42,20 +42,20 @@ button {
 }
 
 :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;