Settings: Shake the overlay when the user clicks on the overlay shield.

chrome/browser/resources/shared/css/overlay.css

 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
 /* The shield that overlays the background. */
 .overlay {
   -webkit-box-align: center;
   -webkit-box-orient: vertical;
   -webkit-box-pack: center;
   -webkit-transition: 200ms opacity;
   background-color: rgba(255, 255, 255, 0.75);
   bottom: 0;
   display: -webkit-box;
   left: 0;
   overflow: auto;
   padding: 20px;
   padding-bottom: 130px;
   position: fixed;
   right: 0;
   top: 0;
 }
 
-/* The foregrounded dialog. */

[csilv, 2012/02/07 18:57:33]

lol

+/* The foreground dialog. */
 .overlay .page {
   background: white;
   box-shadow: 0 3px 15px rgba(0, 0, 0, 0.3), 0 3px 57px rgba(0, 0, 0, 0.3);
   min-width: 400px;
   padding: 0;
   position: relative;
 }
 
+/* keyframes used to shake the overlay */
+@-webkit-keyframes shake {
+  0% {
+    -webkit-transform: translateX(-5px) rotateZ(-0.5deg) translateY(-2px);
+  }
+  50% {
+    -webkit-transform: translateX(0px) rotateZ(0deg) translateY(0px);
+  }
+  100% {
+    -webkit-transform: translateX(5px) rotateZ(0.5deg) translateY(-2px);
+  }
+}
+
+.overlay .page.shake {
+  -webkit-animation-direction: alternate;
+  -webkit-animation-duration: 60ms;
+  -webkit-animation-iteration-count: 7;
+  -webkit-animation-name: shake;
+  -webkit-animation-timing-function: ease-in-out;
+}
+
 .overlay .page h1 {
   -webkit-padding-end: 24px;
   -webkit-user-select: none;
   background: -webkit-linear-gradient(white, #F8F8F8);
   border-bottom: 1px solid rgba(188, 193, 208, .5);
   color: #333;
   font-size: 105%;
   font-weight: bold;
   margin: 0;
   padding: 10px 15px 8px;
@@ skipping 23 matching lines @@
 
 .overlay .page .button-strip {
   -webkit-box-orient: horizontal;
   display: -webkit-box;
 }
 
 .overlay .page .button-strip > button {
   -webkit-margin-start: 10px;
   display: block;
 }