MD Settings: Allow controlled-button to be used with icons.

chrome/browser/resources/settings/downloads_page/downloads_page.html

Index: chrome/browser/resources/settings/downloads_page/downloads_page.html
diff --git a/chrome/browser/resources/settings/downloads_page/downloads_page.html b/chrome/browser/resources/settings/downloads_page/downloads_page.html
index 64af1e7a93b9f7e9c60d505dc199c1b2a5b38be8..47e990740a474d3aea8d2c352a43f4f625ce85da 100644
--- a/chrome/browser/resources/settings/downloads_page/downloads_page.html
+++ b/chrome/browser/resources/settings/downloads_page/downloads_page.html
@@ -6,8 +6,13 @@
 
 <dom-module id="settings-downloads-page">
   <template>
-    <style include="settings-shared"></style>
-    <div class="settings-box first two-line">
+    <style include="settings-shared">
+      .settings-box[disabled] {
+        pointer-events: none;
+      }
+    </style>
+    <div class="settings-box first two-line" on-tap="selectDownloadLocation_"
+        disabled$="[[isControlled_]]" actionable>
       <div class="start">
         <div>$i18n{downloadLocation}</div>
         <div class="secondary">
@@ -19,14 +24,10 @@
 </if>
         </div>
       </div>
-      <div class="secondary-action">
-        <controlled-button class="secondary-button" id="changeDownloadsPath"
-            on-tap="selectDownloadLocation_"
-            pref="[[prefs.download.default_directory]]"
-            end-justified>
-          $i18n{changeDownloadLocation}
-        </controlled-button>
-      </div>
+      <controlled-button id="changeDownloadsPath" icon-class="icon-external"
+          pref="[[prefs.download.default_directory]]" end-justified
+          controlled="{{isControlled_}}">
+      </controlled-button>
     </div>
     <div class="settings-box block">
       <settings-toggle-button