Revert "content: convert accessibility notifications to callbacks"

content/public/browser/notification_types.h

Index: content/public/browser/notification_types.h
diff --git a/content/public/browser/notification_types.h b/content/public/browser/notification_types.h
index de035c002e1e8886fe29799decb797bf571bc3b1..cfaafd53610fcefb0312b8fed4278e7c0864a724 100644
--- a/content/public/browser/notification_types.h
+++ b/content/public/browser/notification_types.h
@@ -250,6 +250,21 @@ enum NotificationType {
   // the RenderViewHost, and the details is a DomOperationNotificationDetails.
   NOTIFICATION_DOM_OPERATION_RESPONSE,
 
+  // Indicates that the render view host has received a "load complete"
+  // accessibility notification. The source is the RenderViewHost,
+  // the details are not used.
+  NOTIFICATION_ACCESSIBILITY_LOAD_COMPLETE,
+
+  // Indicates that the render view host has received a "layout complete"
+  // accessibility notification. The source is the RenderViewHost,
+  // the details are not used.
+  NOTIFICATION_ACCESSIBILITY_LAYOUT_COMPLETE,
+
+  // Indicates that the render view host has received an accessibility
+  // notification. other than the ones covered above.
+  // The source is the RenderViewHost, the details are not used.
+  NOTIFICATION_ACCESSIBILITY_OTHER,
+
   // Child Processes ---------------------------------------------------------
 
   // This notification is sent when a child process host has connected to a