[Cleanup] Remove mac code from aura/ash/views

ui/aura/root_window_view_mac.mm

Index: ui/aura/root_window_view_mac.mm
diff --git a/ui/aura/root_window_view_mac.mm b/ui/aura/root_window_view_mac.mm
deleted file mode 100644
index a82100e843467b1a3b945154613e0e028f0335bb..0000000000000000000000000000000000000000
--- a/ui/aura/root_window_view_mac.mm
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#import "ui/aura/root_window_view_mac.h"
-
-@implementation RootWindowView
--(void)setCompositor:(ui::Compositor*)compositor {
-  compositor_ = compositor;
-}
-
-- (void)drawRect:(NSRect)rect {
-  if (compositor_)
-    compositor_->Draw(false);
-}
-@end