Use delegate protocols present in the 10.6 SDK

base/cocoa_protocols_mac.h

+// 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.
+
+#ifndef BASE_COCOA_PROTOCOLS_MAC_H_
+#define BASE_COCOA_PROTOCOLS_MAC_H_
+
+#import <Cocoa/Cocoa.h>
+
+// The Mac OS X 10.6 SDK introduced new protocols used for delegates.  These
+// protocol defintions were not present in earlier releases of the Mac OS X
+// SDK.  In order to support building against the new SDK, which requires
+// delegates to conform to these protocols, and earlier SDKs, which do not
+// define these protocols at all, this file will provide empty protocol
+// definitions when used with earlier SDK versions.
+
+#if !defined(MAC_OS_X_VERSION_10_6) || \
+    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6
+
+#define DEFINE_EMPTY_PROTOCOL(p) \
+@protocol p \
+@end
+
+DEFINE_EMPTY_PROTOCOL(NSAlertDelegate)
+DEFINE_EMPTY_PROTOCOL(NSAnimationDelegate)
+DEFINE_EMPTY_PROTOCOL(NSMenuDelegate)
+DEFINE_EMPTY_PROTOCOL(NSTableViewDataSource)
+DEFINE_EMPTY_PROTOCOL(NSTextFieldDelegate)
+DEFINE_EMPTY_PROTOCOL(NSTextViewDelegate)
+DEFINE_EMPTY_PROTOCOL(NSWindowDelegate)
+
+#undef DEFINE_EMPTY_PROTOCOL
+
+#endif
+
+#endif  // BASE_COCOA_PROTOCOLS_MAC_H_