[Mac] Use -close instead of -performClose.

This ensures the window can close when it has sheets attached, e.g. the "Open File" dialog.

BUG=362444

Review URL: https://codereview.chromium.org/389453003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282600 0039d316-1c4b-4281-b951-d872f2087c98

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

@@ -607,7 +607,7 @@ void NativeAppWindowCocoa::Hide() {
 }
 
 void NativeAppWindowCocoa::Close() {
-  [window() performClose:nil];
+  [window() close];
 }
 
 void NativeAppWindowCocoa::Activate() {