[MD settings] adjusting heights of settings rows; removing two .css files; unifying settings layout

chrome/browser/resources/settings/passwords_and_forms_page/passwords_section.css

Index: chrome/browser/resources/settings/passwords_and_forms_page/passwords_section.css
diff --git a/chrome/browser/resources/settings/passwords_and_forms_page/passwords_section.css b/chrome/browser/resources/settings/passwords_and_forms_page/passwords_section.css
index f9691c12e2f033519381640e0360e9dc786dffbc..b076bab02c18247d3960e9aea40528504076f824 100644
--- a/chrome/browser/resources/settings/passwords_and_forms_page/passwords_section.css
+++ b/chrome/browser/resources/settings/passwords_and_forms_page/passwords_section.css
@@ -2,23 +2,6 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
-.heading {
-  color: gray;
-}
-
-.section {
-  -webkit-padding-start: 32px;
-  padding-top: 16px;
-}
-
-.separator {
-  border-top: 1px solid #e0e0e0;
-}
-
-.separator:first-of-type {
-  border-top: none;
-}
-
 iron-list {
   /* TODO(hcarmona): Make this flex. */
   -webkit-padding-start: 8px;