Ensure the previously active browser window gets the focus after a browser window is closed on OSX.

chrome/browser/ui/cocoa/browser_window_controller.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/ui/cocoa/browser_window_controller.h"
 
 #include <cmath>
 #include <numeric>
 
 #include "base/command_line.h"
@@ skipping 527 matching lines @@
   // Give beforeunload handlers the chance to cancel the close before we hide
   // the window below.
   if (!browser_->ShouldCloseWindow())
     return NO;
 
   // saveWindowPositionIfNeeded: only works if we are the last active
   // window, but orderOut: ends up activating another window, so we
   // have to save the window position before we call orderOut:.
   [self saveWindowPositionIfNeeded];
 
+  // Ensure focus goes to previous active browser window when this
+  // window is ordered out.
+  [BrowserWindowUtils selectPreviousActiveBrowserWindow:browser_.get()];

[pink (ping after 24hrs), 2012/02/03 14:24:55]

What is the behavior of other applications on Mac with regard to panels and
window focus? Why are we usurping what the OS wants to do?

[jennb, 2012/02/03 18:12:06]

Mac's window ordering selects from among the application's windows so the panel
browser windows do not affect other applications.

[pink (ping after 24hrs), 2012/02/03 18:42:23]

I meant what do other applications do in this similar circumstance?

[jennb, 2012/02/03 19:20:30]

Most applications don't modify window levels. When they do, they want to get a
high priority window so it naturally should take precedence in window ordering.
We're using the higher priority without wanting to take precedence, making us a
unique case.

+
   if (!browser_->tabstrip_model()->empty()) {
     // Tab strip isn't empty.  Hide the frame (so it appears to have closed
     // immediately) and close all the tabs, allowing the renderers to shut
     // down. When the tab strip is empty we'll be called back again.
     [[self window] orderOut:self];
     browser_->OnWindowClosing();
     return NO;
   }
 
   // the tab strip is empty, it's ok to close the window
@@ skipping 1577 matching lines @@
 
 - (BOOL)supportsBookmarkBar {
   return [self supportsWindowFeature:Browser::FEATURE_BOOKMARKBAR];
 }
 
 - (BOOL)isTabbedWindow {
   return browser_->is_type_tabbed();
 }
 
 @end  // @implementation BrowserWindowController(WindowType)