Quickly close tabs/window with long-running unload handlers.

chrome/browser/ui/unload_controller.h

Index: chrome/browser/ui/unload_controller.h
diff --git a/chrome/browser/ui/unload_controller.h b/chrome/browser/ui/unload_controller.h
index fb51668b0554bd67d563d351b8c5db5ee7081f75..4f7183d49cdc920d26753a8b86d745af0485fdb3 100644
--- a/chrome/browser/ui/unload_controller.h
+++ b/chrome/browser/ui/unload_controller.h
@@ -23,6 +23,7 @@ class WebContents;
 }
 
 namespace chrome {
+class UnloadDetachedHandler;
 
 class UnloadController : public content::NotificationObserver,

[Ben Goodger (Google), 2012/10/26 19:35:14]

It would be good if you could codify your knowledge of how unload works
(including your changes) in a succinct but complete comment here that explains
how unload handlers are processed.

I separated out this code into this class, and reviewed the original
implementation but it's one of those topics that fits into my brain only when
actively working on it, so a crisp statement of intent here would be very
useful.

[slamm, 2012/10/26 23:16:32]

Done.

                          public TabStripModelObserver {
@@ -62,6 +63,9 @@ class UnloadController : public content::NotificationObserver,
   //             could be pursued.
   bool TabsNeedBeforeUnloadFired();
 
+  // Called when detached tabs (if any) finish closing.
+  void DetachedTabsClosedCallback();
+
  private:
   typedef std::set<content::WebContents*> UnloadListenerSet;
 
@@ -114,11 +118,11 @@ class UnloadController : public content::NotificationObserver,
 
   content::NotificationRegistrar registrar_;
 
-  // Tracks tabs that need there beforeunload event fired before we can
+  // Tracks tabs that need their beforeunload event fired before we can
   // close the browser. Only gets populated when we try to close the browser.
   UnloadListenerSet tabs_needing_before_unload_fired_;
 
-  // Tracks tabs that need there unload event fired before we can
+  // Tracks tabs that need their unload event fired before we can
   // close the browser. Only gets populated when we try to close the browser.
   UnloadListenerSet tabs_needing_unload_fired_;
 
@@ -128,6 +132,9 @@ class UnloadController : public content::NotificationObserver,
   // Browser window isn't just immediately closed.
   bool is_attempting_to_close_browser_;
 
+  // Allow unload handlers to run without holding up the UI.
+  UnloadDetachedHandler* const unload_detached_handler_;
+
   base::WeakPtrFactory<UnloadController> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(UnloadController);