Reduce webkit CSS prefixes in ui/ styles

ui/login/screen_container.css

Index: ui/login/screen_container.css
diff --git a/ui/login/screen_container.css b/ui/login/screen_container.css
index cf505f2dc03bee207feca5658384d909f13d7481..7959c0a67ed2547680870fcd003a49f809440ac2 100644
--- a/ui/login/screen_container.css
+++ b/ui/login/screen_container.css
@@ -6,7 +6,7 @@
 #outer-container {
   -webkit-box-align: center;
   -webkit-box-pack: center;
-  -webkit-perspective: 1px; /* Workaround, see http://crbug.com/360567 */
+  perspective: 1px; /* Workaround, see http://crbug.com/360567 */
   bottom: 57px;  /* Leave space for the header bar */
   display: -webkit-box;
   left: 0;
@@ -18,7 +18,7 @@
 }
 
 .oobe-display #outer-container {
-  -webkit-perspective: 600px;
+  perspective: 600px;
 }
 
 .pin-container.pin-enabled {
@@ -106,7 +106,7 @@
 
 /* Only play this animation when 'down' class is removed. */
 .oobe-display #inner-container:not(.down) {
-  -webkit-transition: transform 200ms ease-in-out;
+  transition: transform 200ms ease-in-out;
 }
 
 .oobe-display #inner-container.down {
@@ -126,7 +126,7 @@
 
 #progress-dots {
   -webkit-box-pack: center;
-  -webkit-transition: opacity 200ms ease-in-out,
+  transition: opacity 200ms ease-in-out,
                       visibility 200ms ease-in-out;
   display: -webkit-box;
   margin-top: 15px;