mac: Refactor browser_window_controller layout logic.

chrome/browser/ui/cocoa/browser_window_cocoa.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.
 
 #include "chrome/browser/ui/cocoa/browser_window_cocoa.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
@@ skipping 505 matching lines @@
         web_contents, start_sync_callback, email);
   }
 }
 #endif
 
 bool BrowserWindowCocoa::IsDownloadShelfVisible() const {
   return [controller_ isDownloadShelfVisible] != NO;
 }
 
 DownloadShelf* BrowserWindowCocoa::GetDownloadShelf() {
+  [controller_ createAndAddDownloadShelf];
   DownloadShelfController* shelfController = [controller_ downloadShelf];
   return [shelfController bridge];
 }
 
 // We allow closing the window here since the real quit decision on Mac is made
 // in [AppController quit:].
 void BrowserWindowCocoa::ConfirmBrowserCloseWithPendingDownloads(
       int download_count,
       Browser::DownloadClosePreventionType dialog_type,
       bool app_modal,
@@ skipping 183 matching lines @@
   if (browser_->bookmark_bar_state() != BookmarkBar::DETACHED)
     return 0;
   return 40;
 }
 
 void BrowserWindowCocoa::ExecuteExtensionCommand(
     const extensions::Extension* extension,
     const extensions::Command& command) {
   [cocoa_controller() executeExtensionCommand:extension->id() command:command];
 }