Add support for constrained windows on os x, based on Avi's GTMWindowSheetController.

chrome/browser/tab_contents/tab_contents.cc

 // 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/tab_contents/tab_contents.h"
 
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
 #include "base/file_version_info.h"
 #include "base/process_util.h"
@@ skipping 753 matching lines @@
 
 void TabContents::ShowPageInfo(const GURL& url,
                                const NavigationEntry::SSLStatus& ssl,
                                bool show_history) {
   if (!delegate_)
     return;
 
   delegate_->ShowPageInfo(profile(), url, ssl, show_history);
 }
 
-#if defined(OS_WIN) || defined(OS_LINUX)
 ConstrainedWindow* TabContents::CreateConstrainedDialog(
       ConstrainedWindowDelegate* delegate) {
   ConstrainedWindow* window =
       ConstrainedWindow::CreateConstrainedDialog(this, delegate);
   child_windows_.push_back(window);
   return window;
 }
-#endif
 
 void TabContents::AddNewContents(TabContents* new_contents,
                                  WindowOpenDisposition disposition,
                                  const gfx::Rect& initial_pos,
                                  bool user_gesture,
                                  const GURL& creator_url) {
   if (!delegate_)
     return;
 
   if ((disposition == NEW_POPUP) && !user_gesture &&
@@ skipping 1610 matching lines @@
       NavigationController::LoadCommittedDetails& committed_details =
           *(Details<NavigationController::LoadCommittedDetails>(details).ptr());
       ExpireInfoBars(committed_details);
       break;
     }
 
     default:
       NOTREACHED();
   }
 }