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>
 
 #include "base/file_path.h"
 #include "base/logging.h"
 #include "base/mac/bundle_locations.h"
 #include "base/mac/foundation_util.h"
 #include "base/mac/mac_logging.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/memory/scoped_generic_obj.h"
 #include "base/memory/scoped_nsobject.h"
 #include "base/string_number_conversions.h"
 #include "base/string_piece.h"
 #include "base/sys_string_conversions.h"
 
+#if !defined(MAC_OS_X_VERSION_10_7) || \
+    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7
+
+// Declare symbols that are part of the 10.7 SDK.
+
+@interface NSEvent (LionSDKDeclarations)
++ (bool)isSwipeTrackingFromScrollEventsEnabled;
+@end
+
+#endif  // MAC_OS_X_VERSION_10_7
+
 namespace base {
 namespace mac {
 
 namespace {
 
 // The current count of outstanding requests for full screen mode from browser
 // windows, plugins, etc.
 int g_full_screen_requests[kNumFullScreenModes] = { 0, 0, 0};
 
 // Sets the appropriate SystemUIMode based on the current full screen requests.
@@ skipping 655 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() {
+  return [NSEvent respondsToSelector:@selector(
+              isSwipeTrackingFromScrollEventsEnabled)]
+      && [NSEvent isSwipeTrackingFromScrollEventsEnabled];
+}
+
 }  // namespace mac
 }  // namespace base