Opt out of macOS Sierra automatic window tabbing

chrome/browser/app_controller_mac.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/app_controller_mac.h"
 
 #include <stddef.h>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
@@ skipping 390 matching lines @@
                            andEventID:'OURL'];
   [[NSNotificationCenter defaultCenter] removeObserver:self];
   [[[NSWorkspace sharedWorkspace] notificationCenter] removeObserver:self];
 }
 
 // (NSApplicationDelegate protocol) This is the Apple-approved place to override
 // the default handlers.
 - (void)applicationWillFinishLaunching:(NSNotification*)notification {
   MacStartupProfiler::GetInstance()->Profile(
       MacStartupProfiler::WILL_FINISH_LAUNCHING);
+
+  if ([NSWindow respondsToSelector:@selector(allowsAutomaticWindowTabbing)]) {

[Nico, 2016/09/12 14:13:58]

is checking for `setAllowsAutomaticWindowTabbing:` more correct since that's
what you're calling? (optional comment, doesn't matter in practice)

[Sidney San Martín, 2016/09/12 15:07:25]

You are technically correct — the best kind of correct.

I thought about this before I submitted. I kept it because even though
`setAllowsAutomaticWindowTabbing:` is the actual method, I feel like
`allowsAutomaticWindowTabbing` more clearly expresses our intent to make sure
the property exists at all.

+    NSWindow.allowsAutomaticWindowTabbing = NO;
+  }
 }
 
 - (void)applicationWillHide:(NSNotification*)notification {
   apps::ExtensionAppShimHandler::OnChromeWillHide();
 }
 
 - (BOOL)tryToTerminateApplication:(NSApplication*)app {
   // Reset this now that we've received the call to terminate.
   BOOL isPoweringOff = isPoweringOff_;
   isPoweringOff_ = NO;
@@ skipping 1258 matching lines @@
 
 //---------------------------------------------------------------------------
 
 namespace app_controller_mac {
 
 bool IsOpeningNewWindow() {
   return g_is_opening_new_window;
 }
 
 }  // namespace app_controller_mac