Split cocoa_event_utils in two parts.

ui/base/cocoa/cocoa_base_utils.mm

+// Copyright 2013 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 "ui/base/cocoa/cocoa_base_utils.h"
+
+#include "ui/events/cocoa/cocoa_event_utils.h"
+
+namespace ui {
+
+WindowOpenDisposition WindowOpenDispositionFromNSEvent(NSEvent* event) {
+  NSUInteger modifiers = [event modifierFlags];
+  return WindowOpenDispositionFromNSEventWithFlags(event, modifiers);
+}
+
+WindowOpenDisposition WindowOpenDispositionFromNSEventWithFlags(
+    NSEvent* event, NSUInteger modifiers) {
+  int event_flags = EventFlagsFromNSEventWithModifiers(event, modifiers);
+  return DispositionFromEventFlags(event_flags);
+}
+
+}  // namespace ui