Unprefix usage of -webkit-transform in tests

LayoutTests/compositing/layer-creation/overlap-transformed-preserved-3d.html

Index: LayoutTests/compositing/layer-creation/overlap-transformed-preserved-3d.html
diff --git a/LayoutTests/compositing/layer-creation/overlap-transformed-preserved-3d.html b/LayoutTests/compositing/layer-creation/overlap-transformed-preserved-3d.html
index 0445f1b1c7746349f97038b2802e46e26586e279..08ea0934a3f15d7ff5100eece923a86487a37bc8 100644
--- a/LayoutTests/compositing/layer-creation/overlap-transformed-preserved-3d.html
+++ b/LayoutTests/compositing/layer-creation/overlap-transformed-preserved-3d.html
@@ -22,12 +22,12 @@
       -webkit-perspective-origin: 50px 50px;
      }
      .rotate-3d-start {
-        -webkit-transform: scale(0.5) rotateX(45deg) rotateY(45deg);
+        transform: scale(0.5) rotateX(45deg) rotateY(45deg);
         -webkit-transform-origin: 50px 50px;
         -webkit-transform-style: preserve-3d;
      }
      .rotate-3d-end {
-        -webkit-transform: scale(1.0) rotateX(45deg) rotateY(45deg);
+        transform: scale(1.0) rotateX(45deg) rotateY(45deg);
       }
     .top {
       top: 0px;
@@ -61,22 +61,22 @@
       -webkit-transform-origin: 50% 50%;
     }
     .side-1 {
-      -webkit-transform: translateZ(50px);
+      transform: translateZ(50px);
     }
     .side-2 {
-      -webkit-transform: rotateY(90deg) translateZ(50px);
+      transform: rotateY(90deg) translateZ(50px);
     }
     .side-3 {
-      -webkit-transform: rotateY(180deg) translateZ(50px);
+      transform: rotateY(180deg) translateZ(50px);
     }
     .side-4 {
-      -webkit-transform: rotateY(270deg) translateZ(50px);
+      transform: rotateY(270deg) translateZ(50px);
     }
     .side-5 {
-      -webkit-transform: rotateX(90deg) translateZ(50px);
+      transform: rotateX(90deg) translateZ(50px);
     }
     .side-6 {
-      -webkit-transform: rotateX(-90deg) translateZ(50px);
+      transform: rotateX(-90deg) translateZ(50px);
     }
   </style>
   <script>