mac: Remove more 10.5-only code

chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm

Index: chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm b/chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm
index 828d4adf7ad538c3e176f701ec34dcc13b3a0b94..ce638bc640d448f4c4e22ef65f5c0d86e6d4d42d 100644
--- a/chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm
+++ b/chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm
@@ -129,7 +129,7 @@ ShellWindowCocoa::ShellWindowCocoa(Profile* profile,
     [window setContentMaxSize:NSMakeSize(max_width, max_height)];
   }
 
-  if (base::mac::IsOSSnowLeopardOrEarlier() &&
+  if (base::mac::IsOSSnowLeopard() &&
       [window respondsToSelector:@selector(setBottomCornerRounded:)])
     [window setBottomCornerRounded:NO];
 
@@ -200,7 +200,7 @@ void ShellWindowCocoa::SetFullscreen(bool fullscreen) {
     return;
   }
 
-  DCHECK(base::mac::IsOSSnowLeopardOrEarlier());
+  DCHECK(base::mac::IsOSSnowLeopard());
 
   // Fade to black.
   const CGDisplayReservationInterval kFadeDurationSeconds = 0.6;