Uber: Limit the height of overlays to the min of 90% of the page or 640px.

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 foreground dialog. */
 .overlay .page {
+  -webkit-box-orient: vertical;
   background: white;
   box-shadow: 0 3px 15px rgba(0, 0, 0, 0.3), 0 3px 57px rgba(0, 0, 0, 0.3);
+  display: -webkit-box;
+  height: 90%;
+  max-height: 640px;
   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);
   }
@@ skipping 20 matching lines @@
   border-bottom: 1px solid rgba(188, 193, 208, .5);
   color: #333;
   font-size: 1.1em;
   font-weight: bold;
   margin: 0;
   padding: 10px 15px 8px;
   text-shadow: white 0 1px 2px;
 }
 
 .overlay .page .content-area {
+  -webkit-box-flex: 1;
+  overflow: auto;
   padding: 10px 15px 5px;
 }
 
 .overlay .page .action-area {
   -webkit-box-align: center;
   -webkit-box-orient: horizontal;
   -webkit-box-pack: end;
   border-top: 1px solid rgba(188, 193, 208, .5);
   display: -webkit-box;
   padding: 12px;
 }
 
 html[dir='rtl'] .overlay .page .action-area {
   left: 0;
 }
 
 .overlay .page .action-area-right {
   display: -webkit-box;
 }
 
 .overlay .page .button-strip {
   -webkit-box-orient: horizontal;
   display: -webkit-box;
 }
 
 .overlay .page .button-strip > button {
   -webkit-margin-start: 10px;
   display: block;
 }