Fix sizing issues in the tab modal signin flow.

chrome/browser/resources/sync_confirmation/sync_confirmation.css

 /* Copyright 2015 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. */
 
 body {
   margin: 0;
   padding: 0;
 }
 
 a {
   color: rgb(85, 149, 254);
   text-decoration: none;
 }
 
 .picture img {
   border-radius: 50%;
   max-height: 100%;
   max-width: 100%;
 }
 
 .container {
   background-color: white;
-  height: 351px;
   overflow: hidden;
   width: 448px;
 }
 
 .top-title-bar {
   -webkit-padding-start: 24px;
   align-items: center;
   border-bottom: 1px solid lightgray;
   color: #333;
   display: flex;
   font-size: 16px;
   height: 52px;
 }
 
 .details {
-  height: 250px;
+  font-size: 13px;
   padding: 20px 24px;
 }
 
 .sync-message {
   color: #595959;
   line-height: 150%;
   padding-bottom: 32px;
 }
 
 #picture-container {
@@ skipping 267 matching lines @@
 @keyframes fade-in-icon-bottom-right {
   from {
     opacity: 0;
     transform: translate(0, 0);
   }
   to {
     opacity: 0.1;
     transform: translate(4px, 4px);
   }
 }