Upstream Chrome on iOS source code [8/11].

ios/chrome/browser/ui/side_swipe/side_swipe_util.mm

+// Copyright 2015 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.
+
+#import "ios/chrome/browser/ui/side_swipe/side_swipe_util.h"
+
+#import <UIKit/UIKit.h>
+
+#include "ios/chrome/browser/ui/rtl_geometry.h"
+
+BOOL IsSwipingBack(UISwipeGestureRecognizerDirection direction) {
+  if (UseRTLLayout())
+    return direction == UISwipeGestureRecognizerDirectionLeft;
+  else
+    return direction == UISwipeGestureRecognizerDirectionRight;
+}
+
+BOOL IsSwipingForward(UISwipeGestureRecognizerDirection direction) {
+  if (UseRTLLayout())
+    return direction == UISwipeGestureRecognizerDirectionRight;
+  else
+    return direction == UISwipeGestureRecognizerDirectionLeft;
+}