Show data usage on Site Details (MDSettings)

chrome/browser/resources/settings/site_settings/site_details.js

Index: chrome/browser/resources/settings/site_settings/site_details.js
diff --git a/chrome/browser/resources/settings/site_settings/site_details.js b/chrome/browser/resources/settings/site_settings/site_details.js
index a6a8db7bccd77c5cc7efe83b5ed76db48c90c85d..c2a609eb3d8d45882b9df412c975e13d8278b4eb 100644
--- a/chrome/browser/resources/settings/site_settings/site_details.js
+++ b/chrome/browser/resources/settings/site_settings/site_details.js
@@ -31,15 +31,15 @@ Polymer({
     /**
      * The origin that this widget is showing details for.
      */
-    origin: String,
+    origin: {
+      type: String,
+      observer: 'onOriginChanged_',
+    },
 
     /**
      * The amount of data stored for the origin.
      */
-    storedData_: {
-      type: String,
-      observer: 'onStoredDataChanged_',
-    },
+    storedData_: String,
   },
 
   ready: function() {
@@ -51,19 +51,39 @@ Polymer({
     this.$.fullscreen.category = settings.ContentSettingsTypes.FULLSCREEN;
     this.$.camera.category = settings.ContentSettingsTypes.CAMERA;
     this.$.mic.category = settings.ContentSettingsTypes.MIC;
+  },
 
-    this.storedData_ = '1337 MB';  // TODO(finnur): Fetch actual data.
+  /**
+   * Handler for when the origin changes.
+   */
+  onOriginChanged_: function() {
+    var siteSettingsHandler = new SiteSettingsHandler();
+    siteSettingsHandler.fetchUsageTotal(
+        this.origin,                 // The origin to fetch usage total for.
+        this,                        // The context to use for the callback.
+        this.OnUsageDataAvailable);  // The callback.

[michaelpg, 2016/01/19 20:47:54]

just bind this to |this| instead of passing the |this| object separately

or maybe use a listener? +stevenjb 

[Finnur, 2016/01/22 15:07:35]

Obsolete code now.

   },
 
-  onStoredDataChanged_: function() {
+  /**
+   * Updates the usage data and shows its header.
+   * @param {string} usage The amount of data stored for the current origin.
+   */
+  OnUsageDataAvailable: function(usage) {

[michaelpg, 2016/01/19 20:47:54]

camelCase

also, would you mind renaming this? i find it confusing that
OnUsageDataAvailable is also defined on SiteSettingsHandler.

[Finnur, 2016/01/22 15:07:35]

Also obsolete.

+    this.storedData_ = usage;
     this.$.usage.hidden = false;
     this.$.storage.hidden = false;
   },
 
+  /**
+   * Clears all data stored for the current origin.
+   */
   onClearStorage_: function() {
     // TODO(finnur): Implement.
   },
 
+  /**
+   * Resets all permissions and clears all data stored for the current origin.
+   */
   onClearAndReset_: function() {
     Array.prototype.forEach.call(
         this.root.querySelectorAll('site-details-permission'),