make NavigationGesture part of public content API and use it outside content

content/common/navigation_gesture.h

-// 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.
-
-#ifndef CONTENT_COMMON_NAVIGATION_GESTURE_H_
-#define CONTENT_COMMON_NAVIGATION_GESTURE_H_
-
-namespace content {
-
-enum NavigationGesture {
-  // User initiated navigation/load.
-  NavigationGestureUser,
-  // Non-user initiated navigation/load. For example, onload- or
-  // setTimeout-triggered document.location changes and form.submits.  See
-  // http://b/1046841 for some cases that should be treated this way but aren't.
-  NavigationGestureAuto,
-  // Initial state.
-  NavigationGestureUnknown,
-  NavigationGestureLast = NavigationGestureUnknown
-};
-
-}  // namespace content
-
-#endif  // CONTENT_COMMON_NAVIGATION_GESTURE_H_