Have LazyBackgroundTaskQueue notify consumers when the transient page fails to

chrome/browser/extensions/extension_message_service.h

Index: chrome/browser/extensions/extension_message_service.h
diff --git a/chrome/browser/extensions/extension_message_service.h b/chrome/browser/extensions/extension_message_service.h
index 3f3a7bdf9c7ee1aa1fcdf627538ec0136187df19..ab64160c47c37cbeb5ed7f1c8dc5d75734f6dd76 100644
--- a/chrome/browser/extensions/extension_message_service.h
+++ b/chrome/browser/extensions/extension_message_service.h
@@ -126,13 +126,17 @@ class ExtensionMessageService : public content::NotificationObserver {
   void PendingOpenChannel(const OpenChannelParams& params,
                           int source_process_id,
                           ExtensionHost* host);
-  void PendingCloseChannel(int port_id, bool connection_error, ExtensionHost*) {
-    CloseChannel(port_id, connection_error);
+  void PendingCloseChannel(int port_id,
+                           bool connection_error,
+                           ExtensionHost* host) {
+    if (host)
+      CloseChannel(port_id, connection_error);
   }
   void PendingPostMessage(int port_id,
                           const std::string& message,
-                          ExtensionHost*) {
-    PostMessageFromRenderer(port_id, message);
+                          ExtensionHost* host) {
+    if (host)
+      PostMessageFromRenderer(port_id, message);
   }
 
   content::NotificationRegistrar registrar_;