CSS Animations: Remove unnecessary webkit prefixes from layout tests

third_party/WebKit/LayoutTests/animations/empty-keyframes.html

Index: third_party/WebKit/LayoutTests/animations/empty-keyframes.html
diff --git a/third_party/WebKit/LayoutTests/animations/empty-keyframes.html b/third_party/WebKit/LayoutTests/animations/empty-keyframes.html
index 0d914ebbe18035f91b9316b91c1836f2b0d5cef4..492481bd223a4e73fe4dcac03c14a6038d6fbc13 100644
--- a/third_party/WebKit/LayoutTests/animations/empty-keyframes.html
+++ b/third_party/WebKit/LayoutTests/animations/empty-keyframes.html
@@ -7,13 +7,13 @@
   <title>Empty keyframes</title>
   <style type="text/css" media="screen">
     #box {
-      -webkit-animation-name: test, test-one;
-      -webkit-animation-duration: 1s;
+      animation-name: test, test-one;
+      animation-duration: 1s;
     }
-    @-webkit-keyframes test {
+    @keyframes test {
     }
 
-    @-webkit-keyframes test-one {
+    @keyframes test-one {
       0% {}
     }
   </style>