[Mac] A more robust way to ensure panels avoid key status on window close

chrome/browser/ui/cocoa/apps/app_shim_menu_controller_mac.mm

 // Copyright 2013 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/apps/app_shim_menu_controller_mac.h"
 
 #include "base/mac/scoped_nsautorelease_pool.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
@@ skipping 355 matching lines @@
 }
 
 - (void)windowMainStatusChanged:(NSNotification*)notification {
   // A Yosemite AppKit bug causes this notification to be sent during the
   // -dealloc for a specific NSWindow. Any autoreleases sent to that window
   // must be drained before the window finishes -dealloc. In this method, an
   // autorelease is sent by the invocation of [NSApp windows].
   // http://crbug.com/406944.
   base::mac::ScopedNSAutoreleasePool pool;
 
-  id window = [notification object];
   NSString* name = [notification name];
   if ([name isEqualToString:NSWindowDidBecomeMainNotification]) {
+    id window = [notification object];
     extensions::AppWindow* appWindow =
         AppWindowRegistryUtil::GetAppWindowForNativeWindowAnyProfile(
             window);
 
     const extensions::Extension* extension = NULL;
     // If there is no corresponding AppWindow, this could be a hosted app, so
     // check for a browser.
     if (appWindow)
       extension = appWindow->GetExtension();
     else
       extension = apps::ExtensionAppShimHandler::GetAppForBrowser(
           chrome::FindBrowserWithWindow(window));
 
     if (extension)
       [self addMenuItems:extension];
     else
       [self removeMenuItems];
   } else if ([name isEqualToString:NSWindowWillCloseNotification]) {
-    // If there are any other windows that can become main, leave the menu. It
-    // will be changed when another window becomes main. Otherwise, restore the
-    // Chrome menu.
-    for (NSWindow* w : [NSApp windows]) {
-      if ([w canBecomeMainWindow] && ![w isEqual:window] && [w isOnActiveSpace])
-        return;
-    }
-
+    // Always reset back to the Chrome menu. This once scanned [NSApp windows]
+    // to predict whether we could expect another Chrome window to become main,
+    // and skip the reset. However, panels need to do strange things during
+    // window close to ensure panels never get chosen for key status over a
+    // browser window (which is likely because they are given an elevated
+    // [NSWindow level]). Trying to handle this case is not robust.
+    // Unfortunately, resetting the menu to Chrome unconditionally means that
+    // if another packaged app window becomes key, the menu will flicker.
+    // TODO(tapted): Investigate restoring the logic when the panel code is
+    // removed.
     [self removeMenuItems];
   } else {
     NOTREACHED();
   }
 }
 
 - (void)addMenuItems:(const extensions::Extension*)app {
   NSString* appId = base::SysUTF8ToNSString(app->id());
   NSString* title = base::SysUTF8ToNSString(app->name());
 
@@ skipping 97 matching lines @@
 
 - (void)focusCurrentPlatformApp {
   extensions::AppWindow* appWindow =
       AppWindowRegistryUtil::GetAppWindowForNativeWindowAnyProfile(
           [NSApp keyWindow]);
   if (appWindow)
     apps::ExtensionAppShimHandler::FocusAppForWindow(appWindow);
 }
 
 @end