CSS Animations: Remove unnecessary webkit prefixes from layout tests

third_party/WebKit/LayoutTests/animations/cascade-important.html

Index: third_party/WebKit/LayoutTests/animations/cascade-important.html
diff --git a/third_party/WebKit/LayoutTests/animations/cascade-important.html b/third_party/WebKit/LayoutTests/animations/cascade-important.html
index 23b51e4508f7798a311010ae15d997e6f39dbbfe..e9803bdf29396461c39f9a54d0796212e1fe19a7 100644
--- a/third_party/WebKit/LayoutTests/animations/cascade-important.html
+++ b/third_party/WebKit/LayoutTests/animations/cascade-important.html
@@ -6,9 +6,9 @@
       width: 100px;
       height: 100px;
       background-color: green !important;
-      -webkit-animation: test 0.5s;
+      animation: test 0.5s;
     }
-    @-webkit-keyframes test {
+    @keyframes test {
         from { background-color: red; }
         to { background-color: red; }
     }