MD Settings: fix overflow scrolling for <settings-dialog>

chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_dialog.html

Index: chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_dialog.html
diff --git a/chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_dialog.html b/chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_dialog.html
index 1f2f4e6965e588e0c85fc510b7718285a75d4dc1..8a9d431ed0b49281dbebada3f3b6afc7dab2e4b6 100644
--- a/chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_dialog.html
+++ b/chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_dialog.html
@@ -17,6 +17,20 @@
         max-width: 600px;
       }
 
+      #dialog:not(.fully-rendered) {
+        visibility: hidden;
+      }
+
+      .row {
+        align-items: center;
+        display: flex;
+        min-height: 40px;
+      }
+
+      .row .start {
+        flex: 1;
+      }
+
       paper-spinner {
         -webkit-margin-end: 16px;
         margin-bottom: auto;