MD Settings: Lazy-load sub-pages.

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

Index: chrome/browser/resources/settings/site_settings/site_settings_category.js
diff --git a/chrome/browser/resources/settings/site_settings/site_settings_category.js b/chrome/browser/resources/settings/site_settings/site_settings_category.js
index e98b5caa82fe3eaafc9f52e633c314602185dc4a..ade8a555ec534b7a61812df48859ba3990b4a216 100644
--- a/chrome/browser/resources/settings/site_settings/site_settings_category.js
+++ b/chrome/browser/resources/settings/site_settings/site_settings_category.js
@@ -137,9 +137,10 @@ Polymer({
    * @private
    */
   onCategoryChanged_: function() {
-    this.prefsProxy_.getDefaultValueForContentType(
-        this.category).then(function(enabled) {
-          this.categoryEnabled = enabled;
-        }.bind(this));
+    settings.SiteSettingsPrefsBrowserProxyImpl.getInstance()

[Dan Beam, 2016/03/25 03:21:59]

why was this necessary?

[michaelpg, 2016/03/29 22:04:03]

when navigating to site-settings directly, this is now called before ready, so
the BrowserProxy hasn't been created yet, so this throws.

fwiw, i'm not 100% sure site settings works cuz there are bugs in site settings
before my patch.

+        .getDefaultValueForContentType(
+            this.category).then(function(enabled) {
+              this.categoryEnabled = enabled;
+            }.bind(this));
   },
 });