Revert r42156, r42157, r42160. Allow dynamic switching in and out of sidetabs...

chrome/browser/cocoa/browser_window_cocoa.mm

 // Copyright (c) 2010 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.
 
 #include "chrome/browser/cocoa/browser_window_cocoa.h"
 
 #include "app/l10n_util_mac.h"
 #include "base/keyboard_codes.h"
 #include "base/logging.h"
 #include "base/sys_string_conversions.h"
@@ skipping 522 matching lines @@
 }
 
 void BrowserWindowCocoa::Copy() {
   [NSApp sendAction:@selector(copy:) to:nil from:nil];
 }
 
 void BrowserWindowCocoa::Paste() {
   [NSApp sendAction:@selector(paste:) to:nil from:nil];
 }
 
-void BrowserWindowCocoa::ToggleTabStripMode() {
-  NOTIMPLEMENTED();
-}
-
 void BrowserWindowCocoa::Observe(NotificationType type,
                                  const NotificationSource& source,
                                  const NotificationDetails& details) {
   switch (type.value) {
     // Only the key window gets a direct toggle from the menu.
     // Other windows hear about it from the notification.
     case NotificationType::BOOKMARK_BAR_VISIBILITY_PREF_CHANGED:
       [controller_ updateBookmarkBarVisibilityWithAnimation:YES];
       break;
     default:
       NOTREACHED();  // we don't ask for anything else!
       break;
   }
 }
 
 void BrowserWindowCocoa::DestroyBrowser() {
   [controller_ destroyBrowser];
 
   // at this point the controller is dead (autoreleased), so
   // make sure we don't try to reference it any more.
 }
 
 NSWindow* BrowserWindowCocoa::window() const {
   return [controller_ window];
 }