Fix bug where transient pages would miss events dispatched while it was

chrome/browser/extensions/lazy_background_task_queue.h

Index: chrome/browser/extensions/lazy_background_task_queue.h
diff --git a/chrome/browser/extensions/lazy_background_task_queue.h b/chrome/browser/extensions/lazy_background_task_queue.h
index 12b85ba73049d51f84c15d84801464815d0c8deb..abe71b21865a2647572f8747e787e0018e064289 100644
--- a/chrome/browser/extensions/lazy_background_task_queue.h
+++ b/chrome/browser/extensions/lazy_background_task_queue.h
@@ -7,11 +7,13 @@
 #pragma once
 
 #include <map>
+#include <set>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/callback_forward.h"
 #include "base/memory/linked_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
@@ -27,7 +29,9 @@ namespace extensions {
 //
 // It is the consumer's responsibility to use this class when appropriate, i.e.
 // only with extensions that have not-yet-loaded lazy background pages.
-class LazyBackgroundTaskQueue : public content::NotificationObserver {
+class LazyBackgroundTaskQueue
+    : public content::NotificationObserver,
+      public base::SupportsWeakPtr<LazyBackgroundTaskQueue> {
  public:
   typedef base::Callback<void(ExtensionHost*)> PendingTask;
 
@@ -56,6 +60,10 @@ class LazyBackgroundTaskQueue : public content::NotificationObserver {
   typedef std::vector<PendingTask> PendingTasksList;
   typedef std::map<PendingTasksKey,
                    linked_ptr<PendingTasksList> > PendingTasksMap;
+  typedef std::set<PendingTasksKey> PendingPageLoadList;
+
+  void StartLazyBackgroundPage(Profile* profile,
+                               const std::string& extension_id);
 
   // content::NotificationObserver interface.
   virtual void Observe(int type,
@@ -72,6 +80,7 @@ class LazyBackgroundTaskQueue : public content::NotificationObserver {
   Profile* profile_;
   content::NotificationRegistrar registrar_;
   PendingTasksMap pending_tasks_;
+  PendingPageLoadList pending_page_loads_;
 };
 
 }  // namespace extensions