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

chrome/browser/chrome_browser_application_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/chrome_browser_application_mac.h"
 
 #import "base/auto_reset.h"
 #include "base/debug/crash_logging.h"
 #include "base/debug/stack_trace.h"
 #import "base/logging.h"
@@ skipping 633 matching lines @@
 - (void)_cycleWindowsReversed:(BOOL)arg1 {
   base::AutoReset<BOOL> pin(&cyclingWindows_, YES);
   [super _cycleWindowsReversed:arg1];
 }
 
 - (BOOL)isCyclingWindows {
   return cyclingWindows_;
 }
 
 - (id)_removeWindow:(NSWindow*)window {
+  // Note _removeWindow is called from -[NSWindow dealloc], which can happen at
+  // unpredictable times due to reference counting. Just update state.
   {
     base::AutoLock lock(previousKeyWindowsLock_);
     [self removePreviousKeyWindow:window];
   }
-  id result = [super _removeWindow:window];
-
-  // Ensure app has a key window after a window is removed.
-  // OS wants to make a panel browser window key after closing an app window
-  // because panels use a higher priority window level, but panel windows may
-  // refuse to become key, leaving the app with no key window. The OS does
-  // not seem to consider other windows after the first window chosen refuses
-  // to become key. Force consideration of other windows here.
-  if ([self isActive] && [self keyWindow] == nil) {
-    NSWindow* key =
-        [self makeWindowsPerform:@selector(canBecomeKeyWindow) inOrder:YES];
-    [key makeKeyWindow];
-  }
-
-  // Return result from the super class. It appears to be the app that
-  // owns the removed window (determined via experimentation).
-  return result;
+  return [super _removeWindow:window];
 }
 
 - (id)_setKeyWindow:(NSWindow*)window {
   // |window| is nil when the current key window is being closed.
   // A separate call follows with a new value when a new key window is set.
   // Closed windows are not tracked in previousKeyWindows_.
   if (window != nil) {
     base::AutoLock lock(previousKeyWindowsLock_);
     [self removePreviousKeyWindow:window];
     NSWindow* currentKeyWindow = [self keyWindow];
@@ skipping 14 matching lines @@
   std::vector<NSWindow*>::iterator window_iterator =
       std::find(previousKeyWindows_.begin(),
                 previousKeyWindows_.end(),
                 window);
   if (window_iterator != previousKeyWindows_.end()) {
     previousKeyWindows_.erase(window_iterator);
   }
 }
 
 @end