Enable gesture events for wheel events on all platforms other that OSX.

content/common/input/input_event_utils.cc

Index: content/common/input/input_event_utils.cc
diff --git a/content/common/input/input_event_utils.cc b/content/common/input/input_event_utils.cc
index 925452f56d9bb821465afb28bac9dde72f0813a8..6bd9eaeb03013d6cb86b3edba5a38f0ab2a3236e 100644
--- a/content/common/input/input_event_utils.cc
+++ b/content/common/input/input_event_utils.cc
@@ -11,7 +11,13 @@ namespace content {
 
 bool UseGestureBasedWheelScrolling() {
   base::CommandLine* cmd = base::CommandLine::ForCurrentProcess();
+// TODO(dtapuska): OSX has special code to deal with mouse wheel
+// and overscroll that needs to be fixed. crbug.com/587979
+#if defined(OS_MACOSX)
   return cmd->HasSwitch(switches::kEnableWheelGestures);
+#else
+  return !cmd->HasSwitch(switches::kDisableWheelGestures);
+#endif
 }
 
 }  // namespace content