Mac: Prevent NTP mousewheel events from being suppressed on Lion.

base/mac/mac_util.mm

 // 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.
 
 #include "base/mac/mac_util.h"
 
 #import <Cocoa/Cocoa.h>
 #import <IOKit/IOKitLib.h>
 #include <string.h>
 #include <sys/utsname.h>
@@ skipping 678 matching lines @@
           StringPiece(begin + number_loc, begin + comma_loc), &major_tmp) ||
       !StringToInt(
           StringPiece(begin + comma_loc + 1, ident.end()), &minor_tmp))
     return false;
   *type = ident.substr(0, number_loc);
   *major = major_tmp;
   *minor = minor_tmp;
   return true;
 }
 
+bool IsSwipeTrackingFromScrollEventsEnabled() {
+  SEL selector = @selector(isSwipeTrackingFromScrollEventsEnabled);
+  return [NSEvent respondsToSelector:selector]
+      && [NSEvent performSelector:selector];
+}
+
 }  // namespace mac
 }  // namespace base