Remove all the OS X 10.6 SDK forward declarations.

chrome/browser/app_controller_mac.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/app_controller_mac.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/file_path.h"
@@ skipping 64 matching lines @@
 #include "net/base/net_util.h"
 #include "ui/base/accelerators/accelerator_cocoa.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 
 using content::BrowserContext;
 using content::BrowserThread;
 using content::DownloadManager;
 using content::UserMetricsAction;
 
-// 10.6 adds a public API for the Spotlight-backed search menu item in the Help
-// menu.  Provide the declaration so it can be called below when building with
-// the 10.5 SDK.
-#if !defined(MAC_OS_X_VERSION_10_6) || \
-    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6
-@interface NSApplication (SnowLeopardSDKDeclarations)
-- (void)setHelpMenu:(NSMenu*)helpMenu;
-@end
-#endif
-
 namespace {
 
 // Declare notification names from the 10.7 SDK.
 #if !defined(MAC_OS_X_VERSION_10_7) || \
     MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7
 NSString* NSPopoverDidShowNotification = @"NSPopoverDidShowNotification";
 NSString* NSPopoverDidCloseNotification = @"NSPopoverDidCloseNotification";
 #endif
 
 // True while AppController is calling chrome::NewEmptyWindow(). We need a
@@ skipping 1213 matching lines @@
 
 }  // namespace browser
 
 namespace app_controller_mac {
 
 bool IsOpeningNewWindow() {
   return g_is_opening_new_window;
 }
 
 }  // namespace app_controller_mac