Adapt crOS Encryption Migration for small devices

This commit adapts the encryption migration screen on crOS for devices
with a small screen. It also improves the messages in the event of
insufficient space.

Tested locally

Bug: 1002097
Change-Id: I6afb449e8499047f029b8c0159df4c9cea72d3a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1845218
Commit-Queue: Renato Silva <rrsilva@google.com>
Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705033}

chrome/browser/resources/chromeos/login/encryption_migration.css

@@ -2,15 +2,6 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
-oobe-dialog {
-  height: 640px;
-  /* Subtracting LoginShelfView's height. */
-  max-height: calc(100vh - var(--shelf-area-height));
-  max-width: 100vw;
-  min-height: 0 !important;  /* Making <oobe-dialog> shrinkable. */
-  min-width: 0 !important;  /* Making <oobe-dialog> shrinkable. */
-  width: 768px;
-}
 
 oobe-dialog div {
   line-height: 1.54;  /* 20px height for 13px font. */
@@ -44,10 +35,6 @@ oobe-dialog > iron-icon.warning {
   background-color: var(--google-red-500);
 }
 
-[slot='footer'] {
-  overflow: hidden;
-}
-
 [slot='footer'] div {
   color: rgb(51, 51, 51);
   font-size: 13px;

chrome/browser/resources/chromeos/login/encryption_migration.html

@@ -31,7 +31,8 @@
         <template is="dom-if" if="[[isEnoughBattery]]">
           <div slot="footer" class="layout vertical center">
             <img srcset="images/security_update_1x.png 1x,
-                         images/security_update_2x.png 2x">
+                         images/security_update_2x.png 2x"
+                 class="oobe-illustration">
           </div>
         </template>
         <template is="dom-if" if="[[!isEnoughBattery]]">