CSS manual tests: reduce usage of webkit prefix

third_party/WebKit/ManualTests/animation/compositor-neutral-keyframes.html

Index: third_party/WebKit/ManualTests/animation/compositor-neutral-keyframes.html
diff --git a/third_party/WebKit/ManualTests/animation/compositor-neutral-keyframes.html b/third_party/WebKit/ManualTests/animation/compositor-neutral-keyframes.html
index ec44af15a28463b3716b927e5e3afcb210788b9c..fb725441ec03c589ebe351dec2b24a25813c509a 100644
--- a/third_party/WebKit/ManualTests/animation/compositor-neutral-keyframes.html
+++ b/third_party/WebKit/ManualTests/animation/compositor-neutral-keyframes.html
@@ -7,26 +7,26 @@ div {
     background: blue;
     will-change: transform;
     left: 0px;
-    -webkit-animation-duration: 2s;
-    -webkit-animation-timing-function: linear;
-    -webkit-animation-iteration-count: 2;
+    animation-duration: 2s;
+    animation-timing-function: linear;
+    animation-iteration-count: 2;
 }
 
 .anim-left {
-    -webkit-animation-name: anim-left;
+    animation-name: anim-left;
     z-index: 100;
 }
 
 .anim-transform {
-    -webkit-animation-name: anim-transform;
+    animation-name: anim-transform;
     z-index: 200;
 }
 
-@-webkit-keyframes anim-left {
+@keyframes anim-left {
     100% { left: 300px; }
 }
 
-@-webkit-keyframes anim-transform {
+@keyframes anim-transform {
     100% { transform: translateX(300px); }
 }
 </style>