bluetooth: Add notification system to internals page.

chrome/browser/resources/bluetooth_internals/sidebar.js

Index: chrome/browser/resources/bluetooth_internals/sidebar.js
diff --git a/chrome/browser/resources/bluetooth_internals/sidebar.js b/chrome/browser/resources/bluetooth_internals/sidebar.js
index 81fcb2ee368ca53f90d27d460c80b8a544f59671..f060e713979238a4cd899271606dd828771254f6 100644
--- a/chrome/browser/resources/bluetooth_internals/sidebar.js
+++ b/chrome/browser/resources/bluetooth_internals/sidebar.js
@@ -45,6 +45,7 @@ cr.define('sidebar', function() {
     close: function() {
       this.sidebarDiv_.classList.remove('open');
       document.body.style.overflow = '';
+      document.dispatchEvent(new CustomEvent('contentfocus'));

[Dan Beam, 2016/12/16 08:42:58]

why is this not named something like 'sidebar-close'?

[mbrunson, 2016/12/16 21:42:30]

The main purpose of these 2 events (contentfocus/contentblur) is to alert
listeners that some UI element is going to block the main content of the page. I
wanted it to be named something generic in case other UI elements are added that
also block the user from accessing the main content (alert overlays, dialog
boxes, etc.). The main use of this is to prevent the snackbar from closing
before the user has a chance to read it and respond.

I can use specific event names if you think that sounds like a bad idea. But I
would have to have the Snackbar know about and subscribe to each event
separately which seems like a more complex way of doing this.

     },
 
     /**
@@ -53,6 +54,7 @@ cr.define('sidebar', function() {
     open: function() {
       document.body.style.overflow = 'hidden';
       this.sidebarDiv_.classList.add('open');
+      document.dispatchEvent(new CustomEvent('contentblur'));
     },
 
     /**