[MD settings] icons for clickable rows

chrome/browser/resources/settings/system_page/system_page.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
+<link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
 <link rel="import" href="/controls/controlled_button.html">
 <link rel="import" href="/controls/settings_checkbox.html">
 <link rel="import" href="/lifetime_browser_proxy.html">
 <link rel="import" href="/prefs/prefs.html">
 <link rel="import" href="/settings_shared_css.html">
 <link rel="import" href="/system_page/system_page_browser_proxy.html">
 
 <dom-module id="settings-system-page">
   <template>
     <style include="settings-shared">
@@ skipping 17 matching lines @@
       <div id="hardware-acceleration">
         <settings-checkbox label="$i18n{hardwareAccelerationLabel}"
             pref="{{prefs.hardware_acceleration_mode.enabled}}">
         </settings-checkbox>
         <template is="dom-if" if="[[shouldShowRestart_(
             prefs.hardware_acceleration_mode.enabled.value)]]">
           <paper-button on-tap="onRestartTap_">$i18n{restart}</paper-button>
         </template>
       </div>
     </div>
-    <div class="settings-box">
-      <controlled-button class="primary-button" pref="[[prefs.proxy]]"
-          on-tap="onChangeProxySettingsTap_">
+    <div class="settings-box two-line"  on-tap="onChangeProxySettingsTap_"
+        actionable>
+      <div class="start">
         $i18n{changeProxySettings}
+        <div class="secondary">$i18n{changeProxySettingsDescription}</div>
+      </div>
+      <!-- TODO(dschuyler): This controlled-button should be replaced with
+           something that shows the controlled icon without being a button. -->
+      <controlled-button pref="[[prefs.proxy]]">

[Dan Beam, 2016/09/27 23:03:53]

but not these?

[dschuyler, 2016/09/28 21:03:26]

I kept the ones that are not a controlled-button.
(As we talked about in person).

       </controlled-button>
+      <button class="icon-external" is="paper-icon-button-light">
+      </button>
     </div>
   </template>
   <script src="/system_page/system_page.js"></script>
 </dom-module>