Fix discover app which was broken with OOBE redesign

* Remove oobe-dialog-host-{height,width} vars. We don't actually use the
vars. This would reduce dependency on OOBE
* Make discover app occupy 100% of the dialog


Bug: 1019857
Change-Id: I58bba1ff78cfa7fe4494f317590aac2d635c3f6c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1893267Reviewed-by: Denis Kuznetsov [CET] <antrim@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Commit-Queue: Roman Sorokin [CET] <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712071}

chrome/browser/resources/chromeos/login/discover/discover_app.css

@@ -2,6 +2,12 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
+html,
+body {
+  height: 100%;
+  width: 100%;
+}
+
 body {
   align-content: center;
   display: flex;

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

@@ -3,11 +3,6 @@
  * found in the LICENSE file.
  */
 
-:root {
-  --oobe-dialog-host-height: 100%;
-  --oobe-dialog-host-width: 100%;
-}
-
  #outer-container {
    align-items: center;
    box-sizing: border-box;

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

@@ -30,8 +30,8 @@
     <link rel="stylesheet" href="oobe_popup_overlay.css">
     <style include="shared-style multidevice-setup-shared ">
       multidevice-setup {
-        --multidevice-setup-height: var(--oobe-dialog-host-height);
-        --multidevice-setup-width: var(--oobe-dialog-host-width);
+        --multidevice-setup-height: 100%;
+        --multidevice-setup-width: 100%;
       }
 
       #multidevice-help-overlay-container {

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

@@ -12,10 +12,10 @@
   border-radius: unset;
   box-shadow: unset;
   flex-direction: column;
-  height: var(--oobe-dialog-host-height);
+  height: 100%;
   min-height: 0;
   position: relative;
-  width: var(--oobe-dialog-host-width);
+  width: 100%;
 }
 
 :host(:not([full-screen-dialog])) {