Clicking tab close with option key close the other tabs.

chrome/browser/ui/cocoa/tabs/tab_strip_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.
 
 #import "chrome/browser/ui/cocoa/tabs/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <limits>
 #include <string>
@@ skipping 725 matching lines @@
         TabStripModel::CLOSE_USER_GESTURE |
         TabStripModel::CLOSE_CREATE_HISTORICAL_TAB);
   } else {
     // Use the standard window close if this is the last tab
     // this prevents the tab from being removed from the model until after
     // the window dissapears
     [[tabStripView_ window] performClose:nil];
   }
 }
 
+// Called when the user closes all tabs except for the current tab.
+// Invoke the |CommandCloseOtherTabs| context menu command.
+- (void)closeOtherTabs:(id)sender {
+  int index = [self modelIndexForTabView:sender];
+  if (tabStripModel_->ContainsIndex(index))
+    tabStripModel_->ExecuteContextMenuCommand(
+        index, TabStripModel::CommandCloseOtherTabs);
+}
+
 // Dispatch context menu commands for the given tab controller.
 - (void)commandDispatch:(TabStripModel::ContextMenuCommand)command
           forController:(TabController*)controller {
   int index = [self modelIndexForTabView:[controller view]];
   if (tabStripModel_->ContainsIndex(index))
     tabStripModel_->ExecuteContextMenuCommand(index, command);
 }
 
 // Returns YES if the specificed command should be enabled for the given
 // controller.
@@ skipping 1265 matching lines @@
   NSInteger index = [self indexFromModelIndex:modelIndex];
   BrowserWindowController* controller =
       (BrowserWindowController*)[[switchView_ window] windowController];
   DCHECK(index >= 0);
   if (index >= 0) {
     [controller setTab:[self viewAtIndex:index] isDraggable:YES];
   }
 }
 
 @end