mac: Remove IsOSSnowLeopard().

ui/base/test/scoped_fake_nswindow_fullscreen.mm

 // Copyright 2015 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/base/test/scoped_fake_nswindow_fullscreen.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/bind.h"
 #import "base/mac/foundation_util.h"
@@ skipping 178 matching lines @@
   // Starting in 10.11, calling -[NSWindow setStyleMask:] can actually invoke
   // the fullscreen transitions we want to fake. So, when set, this will include
   // NSFullScreenWindowMask in the swizzled styleMask so that client code can
   // read it.
   bool style_as_fullscreen_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(Impl);
 };
 
 ScopedFakeNSWindowFullscreen::ScopedFakeNSWindowFullscreen() {
-  // -[NSWindow toggleFullScreen:] does not exist on 10.6, so do nothing.
-  if (base::mac::IsOSSnowLeopard())
-    return;
-
   DCHECK(!g_fake_fullscreen_impl);
   impl_.reset(new Impl);
   g_fake_fullscreen_impl = impl_.get();
 }
 
 ScopedFakeNSWindowFullscreen::~ScopedFakeNSWindowFullscreen() {
   g_fake_fullscreen_impl = nullptr;
 }
 
 }  // namespace test
@@ skipping 18 matching lines @@
   if ((newMask ^ currentMask) & NSFullScreenWindowMask) {
     // Since 10.11, OSX triggers fullscreen transitions via setStyleMask, but
     // the faker doesn't attempt to fake them yet.
     NOTREACHED() << "Can't set NSFullScreenWindowMask while faking fullscreen.";
   }
   newMask &= ~NSFullScreenWindowMask;
   g_fake_fullscreen_impl->SetStyleMaskImplementation()(self, _cmd, newMask);
 }
 
 @end