Reduce webkit CSS prefixes in ui/ styles

ui/webui/resources/images/throbber_medium.svg

 <!-- This version of the throbber is good for size 28x28dp or more. -->
 <svg version="1" xmlns="http://www.w3.org/2000/svg"
                  xmlns:xlink="http://www.w3.org/1999/xlink"
      viewBox="0 0 28 28">
   <!-- 28= RADIUS*2 + STROKEWIDTH -->
 
   <title>Material design circular activity spinner with CSS3 animation</title>
   <style type="text/css">
       /**************************/
       /* STYLES FOR THE SPINNER */
@@ skipping 19 matching lines @@
         height:28px; /* 2*RADIUS + STROKEWIDTH */
       }
       .qp-circular-loader-path {
         stroke-dasharray: 58.9;  /* 2*RADIUS*PI * ARCSIZE/360 */
         stroke-dashoffset: 58.9; /* 2*RADIUS*PI * ARCSIZE/360 */
                                  /* hides things initially */
       }
 
       /* SVG elements seem to have a different default origin */
       .qp-circular-loader, .qp-circular-loader * {
-        -webkit-transform-origin: 50% 50%;
+        transform-origin: 50% 50%;
       }
 
       /* Rotating the whole thing */
-      @-webkit-keyframes rotate {
+      @keyframes rotate {
         from {transform: rotate(0deg);}
         to {transform: rotate(360deg);}
       }
       .qp-circular-loader {
-        -webkit-animation-name: rotate;
-        -webkit-animation-duration: 1568.63ms; /* 360 * ARCTIME / (ARCSTARTROT + (360-ARCSIZE)) */
-        -webkit-animation-iteration-count: infinite;
-        -webkit-animation-timing-function: linear;
+        animation-name: rotate;
+        animation-duration: 1568.63ms; /* 360 * ARCTIME / (ARCSTARTROT + (360-ARCSIZE)) */
+        animation-iteration-count: infinite;
+        animation-timing-function: linear;
       }
 
       /* Filling and unfilling the arc */
-      @-webkit-keyframes fillunfill {
+      @keyframes fillunfill {
         from {
           stroke-dashoffset: 58.8 /* 2*RADIUS*PI * ARCSIZE/360 - 0.1 */
                                   /* 0.1 a bit of a magic constant here */
         }
         50% {
           stroke-dashoffset: 0;
         }
         to {
           stroke-dashoffset: -58.4 /* -(2*RADIUS*PI * ARCSIZE/360 - 0.5) */
                                    /* 0.5 a bit of a magic constant here */
         }
       }
-      @-webkit-keyframes rot {
+      @keyframes rot {
         from {
           transform: rotate(0deg);
         }
         to {
           transform: rotate(-360deg);
         }
       }
-      @-webkit-keyframes colors {
+      @keyframes colors {
         from {
           stroke: #4285f4;
         }
         to {
           stroke: #4285f4;
         }
       }
       .qp-circular-loader-path {
-        -webkit-animation-name: fillunfill, rot, colors;
-        -webkit-animation-duration: 1333ms, 5332ms, 5332ms; /* ARCTIME, 4*ARCTIME, 4*ARCTIME */
-        -webkit-animation-iteration-count: infinite, infinite, infinite;
-        -webkit-animation-timing-function: cubic-bezier(0.4, 0.0, 0.2, 1), steps(4), linear;
-        -webkit-animation-play-state: running, running, running;
-        -webkit-animation-fill-mode: forwards;
+        animation-name: fillunfill, rot, colors;
+        animation-duration: 1333ms, 5332ms, 5332ms; /* ARCTIME, 4*ARCTIME, 4*ARCTIME */
+        animation-iteration-count: infinite, infinite, infinite;
+        animation-timing-function: cubic-bezier(0.4, 0.0, 0.2, 1), steps(4), linear;
+        animation-play-state: running, running, running;
+        animation-fill-mode: forwards;
       }
 
   </style>
 
   <!-- 3= STROKEWIDTH -->
   <!-- 14= RADIUS + STROKEWIDTH/2 -->
   <!-- 12.5= RADIUS -->
   <!-- 1.5=  STROKEWIDTH/2 -->
   <!-- ARCSIZE would affect the 1.5,14 part of this... 1.5,14 is specific to
        270 degress -->
   <g class="qp-circular-loader">
     <path class="qp-circular-loader-path" fill="none" 
           d="M 14,1.5 A 12.5,12.5 0 1 1 1.5,14" stroke-width="3"
           stroke-linecap="round"></path>
   </g>
 </svg>