Remove TabContents from TabStripModelObserver::ActiveTabChanged.

chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm

 // Copyright (c) 2012 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/ui/cocoa/tabs/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 1280 matching lines @@
 
 - (void)tabReplacedWithContents:(content::WebContents*)newContents
                previousContents:(content::WebContents*)oldContents
                         atIndex:(NSInteger)modelIndex {
   NSInteger index = [self indexFromModelIndex:modelIndex];
   TabContentsController* oldController =
       [tabContentsArray_ objectAtIndex:index];
   DCHECK_EQ(oldContents, [oldController webContents]);
 
   // Simply create a new TabContentsController for |newContents| and place it
-  // into the array, replacing |oldContents|.  A ActiveTabChanged notification
+  // into the array, replacing |oldContents|.  An ActiveTabChanged notification
   // will follow, at which point we will install the new view.
   scoped_nsobject<TabContentsController> newController(
       [[TabContentsController alloc] initWithContents:newContents]);
 
   // Bye bye, |oldController|.
   [tabContentsArray_ replaceObjectAtIndex:index withObject:newController];
 
   // Fake a tab changed notification to force tab titles and favicons to update.
   [self tabChangedWithContents:newContents
                        atIndex:modelIndex
@@ skipping 797 matching lines @@
 NSView* GetSheetParentViewForWebContents(WebContents* web_contents) {
   // View hierarchy of the contents view:
   // NSView  -- switchView, same for all tabs
   // +- NSView  -- TabContentsController's view
   //    +- TabContentsViewCocoa
   //
   // Changing it? Do not forget to modify
   // -[TabStripController swapInTabAtIndex:] too.
   return [web_contents->GetNativeView() superview];
 }