Fix tab focus/blur events on tab switch on the Mac

chrome/browser/cocoa/tab_strip_controller.mm

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/cocoa/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <limits>
 
@@ skipping 878 matching lines @@
   TabContentsController* newController =
       [tabContentsArray_ objectAtIndex:index];
   [newController willBecomeSelectedTab];
 
   // Relayout for new tabs and to let the selected tab grow to be larger in
   // size than surrounding tabs if the user has many. This also raises the
   // selected tab to the top.
   [self layoutTabs];
 
   if (oldContents) {
-    oldContents->view()->StoreFocus();
-    oldContents->WasHidden();
+    int index = browser_->GetIndexOfController(&(oldContents->controller()));
+    if (index != -1) {  // When closing a tab, the old tab may be gone.
+      TabContentsController* oldController =
+          [tabContentsArray_ objectAtIndex:index];
+      [oldController willBecomeUnselectedTab];
+      oldContents->view()->StoreFocus();
+      oldContents->WasHidden();
+    }
   }
 
   // Swap in the contents for the new tab.
   [self swapInTabAtIndex:modelIndex];
 
   if (newContents) {
     newContents->DidBecomeSelected();
     newContents->view()->RestoreFocus();
 
     if (newContents->find_ui_active())
@@ skipping 572 matching lines @@
       // Show next sheet
       NSWindowController* controller = [[tab window] windowController];
       DCHECK([controller isKindOfClass:[BrowserWindowController class]]);
       windows.front()->Realize(
           static_cast<BrowserWindowController*>(controller));
     }
   }
 }
 
 @end