Removed NOTIFICATION_BROWSER_CLOSING notification

chrome/browser/ui/browser_list_observer.h

Index: chrome/browser/ui/browser_list_observer.h
diff --git a/chrome/browser/ui/browser_list_observer.h b/chrome/browser/ui/browser_list_observer.h
index 42af6d3086e65261be084bbf6d229111a5fb82cf..3e5b148c9339b85a1d4c04a82ef01999cb99c865 100644
--- a/chrome/browser/ui/browser_list_observer.h
+++ b/chrome/browser/ui/browser_list_observer.h
@@ -14,6 +14,10 @@ class BrowserListObserver {
   // Called immediately after a browser is added to the list
   virtual void OnBrowserAdded(Browser* browser) {}
 
+  // When a browser closes OnBrowserCloseStarted() is called. This may be called
+  // more than once for a particular browser.
+  virtual void OnBrowserCloseStarted(Browser* browser) {}

[sky, 2017/05/09 17:19:28]

Please name this OnBrowserClosing() with a comment something like:

// Called when a Browser starts closing. This is called prior to
// removing the tabs. Removing the tabs may delay or stop the close.

[Alexey Seren, 2017/05/10 10:25:30]

Acknowledged.

+
   // Called immediately after a browser is removed from the list
   virtual void OnBrowserRemoved(Browser* browser) {}