CSS manual tests: reduce usage of webkit prefix

third_party/WebKit/ManualTests/transitions.html

Index: third_party/WebKit/ManualTests/transitions.html
diff --git a/third_party/WebKit/ManualTests/transitions.html b/third_party/WebKit/ManualTests/transitions.html
index 33a9cff3cbb3e0c75cd537bca6907a94799e419d..887ea7e701702828dc83a3eb8c98008f9035ecc3 100644
--- a/third_party/WebKit/ManualTests/transitions.html
+++ b/third_party/WebKit/ManualTests/transitions.html
@@ -8,15 +8,15 @@
     div.green {
         width: 100px;
         background-color: green;
-        -webkit-transition-property: background-color;
-        -webkit-transition-duration: 5s;
+        transition-property: background-color;
+        transition-duration: 5s;
     }
 
     div.square {
         width: 100px;
         height: 100px;
-        -webkit-transition-property: height;
-        -webkit-transition-duration: 2s;
+        transition-property: height;
+        transition-duration: 2s;
     }
 </style>
 <p id="instructions">