MD Settings: minor cleanup of content settings code.

chrome/browser/resources/settings/site_settings/category_default_setting.html

Index: chrome/browser/resources/settings/site_settings/category_default_setting.html
diff --git a/chrome/browser/resources/settings/site_settings/category_default_setting.html b/chrome/browser/resources/settings/site_settings/category_default_setting.html
index f5545bb885d5096397daa519b53ab7c19016a239..86ad11d98d87fcf99c7bcc0447ecabc043ef4be0 100644
--- a/chrome/browser/resources/settings/site_settings/category_default_setting.html
+++ b/chrome/browser/resources/settings/site_settings/category_default_setting.html
@@ -9,17 +9,20 @@
 <dom-module id="category-default-setting">
   <template>
     <style include="settings-shared"></style>
-    <div class="settings-box first two-line">
-      <div class="start secondary">[[sliderDescription_]]</div>
+    <div class="settings-box first">
       <settings-toggle-button id="toggle" pref="{{controlParams_}}"
+          class="start primary-toggle"
+          label="[[sliderDescription_]]"
           disabled$="[[isToggleDisabled_(category)]]">
       </settings-toggle-button>
     </div>
     <template is="dom-if" if="[[subOptionLabel]]">
-      <div class="settings-box">
+      <div class$="settings-box {{subOptionClass_(subOptionSecondary)}}">

[dpapad, 2017/03/23 20:23:49]

Do you need a two way binding here {{...}} instead of [[...]]? It seems
unnecessary.

[scottchen, 2017/03/23 22:51:46]

Done.

         <div class="start">
           [[subOptionLabel]]
-          <div class="secondary">[[subOptionSecondary]]</div>
+          <template is="dom-if" if="[[subOptionSecondary]]">
+            <div class="secondary">[[subOptionSecondary]]</div>
+          </template>

[dschuyler, 2017/03/22 20:30:57]

Can the goal here be achieve with hidden? A template has some weight (cost) to
it. Often the weight of the template is offset by the contents it is containing
(i.e. by ratio the template not that much). On a div (which is
optimized/prioritized by Chrome) the template seems like a lot to hide something
tiny.

[scottchen, 2017/03/23 00:13:58]

Done.

         </div>
         <settings-toggle-button disabled$="[[!controlParams_.value]]"
             id="subOptionToggle" pref="{{subControlParams_}}">