Remove all the OS X 10.6 SDK forward declarations.

chrome/browser/ui/cocoa/extensions/shell_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/extensions/shell_window_cocoa.h"
 
 #include "base/mac/mac_util.h"
 #include "base/sys_string_conversions.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/cocoa/browser_window_utils.h"
 #include "chrome/browser/ui/cocoa/extensions/extension_view_mac.h"
 #include "chrome/common/extensions/extension.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_view.h"
 #import "ui/base/cocoa/underlay_opengl_hosting_window.h"
 
 @interface NSWindow (NSPrivateApis)
 - (void)setBottomCornerRounded:(BOOL)rounded;
 @end
 
-#if !defined(MAC_OS_X_VERSION_10_6) || \
-    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7
-
-@interface NSWindow (SnowLeopardSDKDeclarations)
-- (void)setStyleMask:(NSUInteger)styleMask;
-@end
-
-#endif  // MAC_OS_X_VERSION_10_6
-
 // Replicate specific 10.7 SDK declarations for building with prior SDKs.
 #if !defined(MAC_OS_X_VERSION_10_7) || \
     MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7
 
 @interface NSWindow (LionSDKDeclarations)
 - (void)toggleFullScreen:(id)sender;
 @end
 
 #endif  // MAC_OS_X_VERSION_10_7
 
@@ skipping 282 matching lines @@
   return [window_controller_ window];
 }
 
 // static
 ShellWindow* ShellWindow::CreateImpl(Profile* profile,
                                      const extensions::Extension* extension,
                                      const GURL& url,
                                      const ShellWindow::CreateParams& params) {
   return new ShellWindowCocoa(profile, extension, url, params);
 }