Clicking tab close with option key close the other tabs.

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

 // Copyright (c) 2011 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 "base/mac/mac_util.h"
 #import "chrome/browser/themes/theme_service.h"
 #import "chrome/browser/ui/cocoa/menu_controller.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_controller.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_controller_target.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_view.h"
@@ skipping 126 matching lines @@
   contextMenuModel_.reset(
       [target_ contextMenuModelForController:self
                                 menuDelegate:contextMenuDelegate_.get()]);
   contextMenuController_.reset(
       [[MenuController alloc] initWithModel:contextMenuModel_.get()
                      useWithPopUpButtonCell:NO]);
   return [contextMenuController_ menu];
 }
 
 - (IBAction)closeTab:(id)sender {
+  if (([[NSApp currentEvent] modifierFlags] & NSAlternateKeyMask) &&
+      [[self target] respondsToSelector:@selector(closeOtherTabs:)]) {
+    [[self target] performSelector:@selector(closeOtherTabs:)
+                        withObject:[self view]];
+    return;
+  }
   if ([[self target] respondsToSelector:@selector(closeTab:)]) {
     [[self target] performSelector:@selector(closeTab:)
                         withObject:[self view]];
   }
 }
 
 - (void)setTitle:(NSString*)title {
   [[self view] setToolTip:title];
   if ([self mini] && ![self selected]) {
     TabView* tabView = static_cast<TabView*>([self view]);
@@ skipping 174 matching lines @@
 
 - (void)continueDrag:(NSEvent*)event {
   [[target_ dragController] continueDrag:event];
 }
 
 - (void)endDrag:(NSEvent*)event {
   [[target_ dragController] endDrag:event];
 }
 
 @end