Reduce webkit CSS prefixes in ui/ styles

ui/login/account_picker/screen_account_picker.js

Index: ui/login/account_picker/screen_account_picker.js
diff --git a/ui/login/account_picker/screen_account_picker.js b/ui/login/account_picker/screen_account_picker.js
index 7cac00bc3a4131a61cced2d65def37864f3e96ef..16f94e2fe9e1861934f93ab23697a96db687d86a 100644
--- a/ui/login/account_picker/screen_account_picker.js
+++ b/ui/login/account_picker/screen_account_picker.js
@@ -246,7 +246,7 @@ login.createScreen('AccountPickerScreen', 'account-picker', function() {
           }
         }
         var showBubbleCallback = function() {
-          activatedPod.removeEventListener("webkitTransitionEnd",
+          activatedPod.removeEventListener("transitionend",
               showBubbleCallback);
           $('bubble').showContentForElement(bubbleAnchor,
                                             attachment,
@@ -254,7 +254,7 @@ login.createScreen('AccountPickerScreen', 'account-picker', function() {
                                             BUBBLE_OFFSET,
                                             bubblePositioningPadding, true);
         };
-        activatedPod.addEventListener("webkitTransitionEnd",
+        activatedPod.addEventListener("transitionend",
                                       showBubbleCallback);
         ensureTransitionEndEvent(activatedPod);
       }