Remove all the OS X 10.6 SDK forward declarations.

chrome/browser/ui/cocoa/browser_window_controller_private.mm

Index: chrome/browser/ui/cocoa/browser_window_controller_private.mm
diff --git a/chrome/browser/ui/cocoa/browser_window_controller_private.mm b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
index 669949574dab1f95ba69c7b21803b425dd121215..51541f5d40ef39a131475b3d78a89519a7f244a4 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller_private.mm
+++ b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
@@ -44,21 +44,6 @@
 using content::RenderWidgetHostView;
 using content::WebContents;
 
-// Forward-declare symbols that are part of the 10.6 SDK.
-#if !defined(MAC_OS_X_VERSION_10_6) || \
-    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6
-
-enum {
-  NSApplicationPresentationDefault                    = 0,
-  NSApplicationPresentationAutoHideDock               = (1 <<  0),
-  NSApplicationPresentationHideDock                   = (1 <<  1),
-  NSApplicationPresentationAutoHideMenuBar            = (1 <<  2),
-  NSApplicationPresentationHideMenuBar                = (1 <<  3),
-};
-typedef NSUInteger NSApplicationPresentationOptions;
-
-#endif  // MAC_OS_X_VERSION_10_6
-
 namespace {
 
 // Space between the incognito badge and the right edge of the window.