[MD Extensions] Add the source type on the details page for an extension

chrome/browser/resources/md_extensions/detail_view.js

Index: chrome/browser/resources/md_extensions/detail_view.js
diff --git a/chrome/browser/resources/md_extensions/detail_view.js b/chrome/browser/resources/md_extensions/detail_view.js
index 084483862424ec2a19dbadeed8ea0224d9a46641..c3b0afd930c0f76fdf6ebdb92ee0ab234da9d677 100644
--- a/chrome/browser/resources/md_extensions/detail_view.js
+++ b/chrome/browser/resources/md_extensions/detail_view.js
@@ -90,6 +90,12 @@ cr.define('extensions', function() {
     computeDependentEntry_: function(item) {
       return loadTimeData.getStringF('itemDependentEntry', item.name, item.id);
     },
+
+    /** @private */
+    computeSourceString_: function() {
+      return extensions.getItemSourceString(
+          extensions.getItemSource(this.data));
+    }
   });
 
   return {DetailView: DetailView};