Reduce webkit CSS prefixes in ui/ styles

ui/webui/resources/cr_elements/network/cr_network_icon.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_onc_types.html">
 
 <dom-module id="cr-network-icon">
   <template>
     <style>
       /* Note: we use display: block here to avoid positioning issues related to
          the use of overflow: hidden. */
       :host {
         display: block;
@@ skipping 29 matching lines @@
         top: -300%;
       }
 
       #icon.level4 {
         top: -400%;
       }
 
       /* Connecting animation */
 
       #icon.connecting {
-        -webkit-animation: levels 1s infinite;
-        -webkit-animation-timing-function: steps(4, start);
+        animation: levels 1s infinite;
+        animation-timing-function: steps(4, start);
       }
 
-      @-webkit-keyframes levels {
+      @keyframes levels {
         from {
           top: 0%;
         }
         to {
           top: -400%;
         }
       }
 
       /* Badges. */
       /* Note: These use left/right because we do not reverse the badges for
@@ skipping 22 matching lines @@
         hidden$="[[!technology_]]">
     <img id="roaming" alt=""
         src="chrome://resources/cr_elements/network/badge_roaming.png"
         hidden$="[[!roaming_]]">
     <img id="secure" alt=""
         src="chrome://resources/cr_elements/network/badge_secure.png"
         hidden$="[[!secure_]]">
   </template>
   <script src="cr_network_icon.js"></script>
 </dom-module>