Add detached mode plumbing

content/browser/web_contents/web_contents_view_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 <Carbon/Carbon.h>
 
 #import "content/browser/web_contents/web_contents_view_mac.h"
 
 #include <string>
 
@@ skipping 624 matching lines @@
 }
 
 - (void)viewWillMoveToWindow:(NSWindow*)newWindow {
   NSWindow* oldWindow = [self window];
 
   NSNotificationCenter* notificationCenter =
       [NSNotificationCenter defaultCenter];
 
   // Occlusion is highly undesirable for browser tests, since it will
   // flakily change test behavior.
-  static bool isDisabled = base::CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kDisableBackgroundingOccludedWindowsForTesting);
+  static bool isDisabled =
+      1 ||
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableBackgroundingOccludedWindowsForTesting);
 
   if (!isDisabled) {
     if (oldWindow) {
       [notificationCenter
           removeObserver:self
                     name:NSWindowDidChangeOcclusionStateNotification
                   object:oldWindow];
     }
     if (newWindow) {
       [notificationCenter
@@ skipping 24 matching lines @@
 
 - (void)viewDidHide {
   [self updateWebContentsVisibility];
 }
 
 - (void)viewDidUnhide {
   [self updateWebContentsVisibility];
 }
 
 @end