Consolidate SDK forwards in sdk_forward_declarations.h.

apps/app_shim/chrome_main_app_mode_mac.mm

Index: apps/app_shim/chrome_main_app_mode_mac.mm
diff --git a/apps/app_shim/chrome_main_app_mode_mac.mm b/apps/app_shim/chrome_main_app_mode_mac.mm
index b03391601a05986d021f318dd603dfd7d7978b47..1092142733bf4aad26df875b30ec7e34c419160d 100644
--- a/apps/app_shim/chrome_main_app_mode_mac.mm
+++ b/apps/app_shim/chrome_main_app_mode_mac.mm
@@ -23,6 +23,7 @@
 #include "base/mac/mac_util.h"
 #include "base/mac/scoped_nsautorelease_pool.h"
 #include "base/mac/scoped_nsobject.h"
+#include "base/mac/sdk_forward_declarations.h"
 #include "base/message_loop/message_loop.h"
 #include "base/path_service.h"
 #include "base/strings/string_number_conversions.h"
@@ -39,16 +40,6 @@
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/l10n/l10n_util.h"
 
-// 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 NSApplication (LionSDKDeclarations)
-- (void)disableRelaunchOnLogin;
-@end
-
-#endif  // MAC_OS_X_VERSION_10_7
-
 namespace {
 
 // Timeout in seconds to wait for a reply for the initial Apple Event. Note that