Mac: Use a "less" private API for keeping traffic lights lit while bubbles are showing

chrome/browser/ui/cocoa/chrome_browser_window.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/chrome_browser_window.h"
 
 #include "base/logging.h"
 #include "chrome/browser/themes/theme_properties.h"
 #import "chrome/browser/ui/cocoa/themed_window.h"
 #include "ui/base/theme_provider.h"
 
+@interface NSWindow (Private)
+- (BOOL)hasKeyAppearance;
+@end
+
 @implementation ChromeBrowserWindow
 
 - (const ui::ThemeProvider*)themeProvider {
   id delegate = [self delegate];
   if (![delegate respondsToSelector:@selector(themeProvider)])
     return NULL;
   return [delegate themeProvider];
 }
 
 - (ThemedWindowStyle)themedWindowStyle {
@@ skipping 51 matching lines @@
     theColor =
         [theColor colorUsingColorSpaceName:NSCalibratedWhiteColorSpace];
     if (theColor != nil) {
       return [theColor whiteComponent] >= 0.7;
     }
   }
 
   return NO;
 }
 
+- (BOOL)hasKeyAppearance {
+  // If not key, but a non-main child window without its own traffic lights _is_
+  // key, then show this window with key appearance to keep the traffic lights
+  // lit. This does not currently handle WebModal dialogs, since they are
+  // children of an overlay window. But WebModals also temporarily lose key
+  // status while animating closed, so extra logic is needed to avoid flicker.
+  // Start with an early exit, since this is called for every mouseMove and
+  // every cursor blink in an NSTextField.
+  if (![self isKeyWindow]) {
+    for (NSWindow* child in [self childWindows]) {
+      if ([child isKeyWindow] && ![child isMainWindow] &&
+          ([child styleMask] & NSClosableWindowMask) == 0)
+        return YES;
+    }
+  }
+  return [super hasKeyAppearance];
+}
+
 @end