Show warning text in the user settings page for non-owner users.

chrome/browser/resources/options/chromeos_accounts_options_page.css

 .user-list-table {
   border: 1px solid lightgrey;
   border-collapse: collapse;
   border-spacing: 0;
 }
 
 .user-name-edit-row {
   border: 1px solid lightgrey;
   background-color: #ebeffa;
   padding: 5px;
@@ skipping 60 matching lines @@
 
 #userList[disabled] .remove-user-button {
   visibility: hidden;
 }
 
 #userNameEdit {
   border: 1px solid lightgrey;
   width: 366px;
 }
 
+#ownerOnlyWarning {
+  margin-bottom: 10px;
+}
+
+#ownerOnlyWarning > * {
+  vertical-align: middle;
+}
+
+#warningIcon {
+  width: 17px;
+  height: 17px;
+  display: inline-block;
+  background-repeat: no-repeat;
+  background-image: url('warning.png');
+}
+
 input#userNameEdit:invalid {
   background-color: #ff6666;
 }