MD Settings: hide some things from the a11y tree with role="none" so VoiceOver navigation works

chrome/browser/resources/settings/settings_ui/settings_ui.html

Index: chrome/browser/resources/settings/settings_ui/settings_ui.html
diff --git a/chrome/browser/resources/settings/settings_ui/settings_ui.html b/chrome/browser/resources/settings/settings_ui/settings_ui.html
index fa13cad3c68081b67de771a663c0f3956e21cb17..bef3f67e4f2a06fc9af4d2139fc9da18bd7ded81 100644
--- a/chrome/browser/resources/settings/settings_ui/settings_ui.html
+++ b/chrome/browser/resources/settings/settings_ui/settings_ui.html
@@ -82,6 +82,7 @@
         spinner-active="[[toolbarSpinnerActive_]]"
         menu-label="$i18n{menuButtonLabel}"
         on-search-changed="onSearchChanged_"
+        role="none"
         show-menu>
     </cr-toolbar>
     <dialog id="drawer" is="cr-drawer">
@@ -96,7 +97,7 @@
         </template>
       </div>
     </dialog>
-    <paper-header-panel id="headerPanel" mode="waterfall">
+    <paper-header-panel id="headerPanel" mode="waterfall" role="none">
       <settings-main id="main" prefs="{{prefs}}"
           toolbar-spinner-active="{{toolbarSpinnerActive_}}"
           page-visibility="[[pageVisibility_]]"