Implement http auth login dialog for OS X.

chrome/browser/cocoa/download_request_dialog_delegate_mac.mm

 // Copyright (c) 2009 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.
 
 #include "chrome/browser/cocoa/download_request_dialog_delegate_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "app/l10n_util_mac.h"
 #include "app/message_box_flags.h"
@@ skipping 12 matching lines @@
          contextInfo:(void *)contextInfo;
 @end
 
 @implementation SheetCallback
 - (id)initWithTarget:(DownloadRequestDialogDelegateMac*)target {
   if ((self = [super init]) != nil) {
     target_ = target;
   }
   return self;
 }
-- (void) alertDidEnd:(NSAlert *)alert
-          returnCode:(int)returnCode
-         contextInfo:(void *)contextInfo {
+- (void)alertDidEnd:(NSAlert *)alert
+         returnCode:(int)returnCode
+        contextInfo:(void *)contextInfo {
   target_->SheetDidEnd(returnCode);
 }
 @end
 
 
 // static
 DownloadRequestDialogDelegate* DownloadRequestDialogDelegate::Create(
     TabContents* tab,
     DownloadRequestManager::TabDownloadState* host) {
   return new DownloadRequestDialogDelegateMac(tab, host);
@@ skipping 29 matching lines @@
   window_ = tab->CreateConstrainedDialog(this);
 }
 
 void DownloadRequestDialogDelegateMac::CloseWindow() {
   window_->CloseConstrainedWindow();
 }
 
 void DownloadRequestDialogDelegateMac::DeleteDelegate() {
   if (is_sheet_open()) {
     // Close sheet if it's still open.
-    [NSApp endSheet:[(NSAlert*)sheet() window]];  // class SheetDidEnd().
+    [NSApp endSheet:[(NSAlert*)sheet() window]];  // calls SheetDidEnd().
     DCHECK(responded_);
   }
   if (!responded_) {
-    // Happens if the sheet was never visible
+    // Happens if the sheet was never visible.
     responded_ = true;
     DoCancel();
   }
   DCHECK(!host_);
   delete this;
 }
 
 void DownloadRequestDialogDelegateMac::SheetDidEnd(int returnCode) {
   DCHECK(!responded_);
   if (returnCode == NSAlertFirstButtonReturn) {
     DoAccept();
   } else {
     DoCancel();
   }
   responded_ = true;
 }