Consolidate SDK forwards in sdk_forward_declarations.h.

chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm

Index: chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm b/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm
index e9d72bee2993bf56f4ad20705d203a1b9e874cef..a4ad4eabc04d88a0f14caf214ffa876118597cd7 100644
--- a/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm
+++ b/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm
@@ -8,6 +8,7 @@
 #include "base/command_line.h"
 #include "base/mac/foundation_util.h"
 #include "base/mac/mac_util.h"
+#include "base/mac/sdk_forward_declarations.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/cocoa/browser_window_utils.h"
@@ -49,21 +50,6 @@ using apps::AppWindow;
 - (BOOL)_isTitleHidden;
 @end
 
-// 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
-
-enum {
-  NSWindowCollectionBehaviorFullScreenPrimary = 1 << 7,
-  NSFullScreenWindowMask = 1 << 14
-};
-
-#endif  // MAC_OS_X_VERSION_10_7
-
 namespace {
 
 void SetFullScreenCollectionBehavior(NSWindow* window, bool allow_fullscreen) {