MD Settings Desktop: Set embedder when adding exceptions.

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

Index: chrome/browser/resources/settings/site_settings/add_site_dialog.js
diff --git a/chrome/browser/resources/settings/site_settings/add_site_dialog.js b/chrome/browser/resources/settings/site_settings/add_site_dialog.js
index 29e5216c2e76a3a5f849a62d25119a5e7ae40e1d..c149df5e1f1769d0500f7ca7af5261e04de6c611 100644
--- a/chrome/browser/resources/settings/site_settings/add_site_dialog.js
+++ b/chrome/browser/resources/settings/site_settings/add_site_dialog.js
@@ -61,7 +61,7 @@ Polymer({
       return;  // Can happen when Enter is pressed.
     var pattern = this.addPatternWildcard_(this.site_);
     this.setCategoryPermissionForOrigin(
-        pattern, '', this.category, this.allowException ?
+        pattern, pattern, this.category, this.allowException ?
             settings.PermissionValues.ALLOW : settings.PermissionValues.BLOCK);

[dschuyler, 2016/08/08 18:21:26]

IIUC, this is saying that we want this specific
pattern (by using same pattern in both pattern
args). If that is correct, then LGTM. If I'm 
not right, please tell me more about it
and I'll review it again.

[Finnur, 2016/08/09 11:19:54]

Yeah, that's correct. 

Using '' (as I was doing) is equivalent to wildcard, which causes the 'Embedded
on *' message to appear.

In the old content settings system, if you add [*.]google.com, that pattern gets
used in both places, so this matches that.

     this.$.dialog.close();
   },