[iOS] Upstream //ios/chrome/browser/ui

ios/chrome/browser/ui/side_swipe_gesture_recognizer.h

+// Copyright 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 IOS_CHROME_BROWSER_UI_SIDE_SWIPE_GESTURE_RECOGNIZER_H_
+#define IOS_CHROME_BROWSER_UI_SIDE_SWIPE_GESTURE_RECOGNIZER_H_
+
+#import <UIKit/UIGestureRecognizerSubclass.h>
+#import <UIKit/UIKit.h>
+
+// This gesture recognizer is used because the default swipe gesture recognizer
+// is too restrictive.  The default swipe requires a particular velocity and
+// distance that Chrome does not require.
+// Another benefit of using a custom gesture recognizer is it can fail faster,
+// so recognizers that depend on this recognizer can begin faster.
+@interface SideSwipeGestureRecognizer : UIPanGestureRecognizer
+
+// The distance from the edge of the screen in which a side swipe can start.
+@property(nonatomic, assign) CGFloat swipeEdge;
+// The distance from the edge of the screen from which a gesture starts.
+@property(readonly, nonatomic) CGFloat swipeOffset;
+@property(nonatomic, assign) UISwipeGestureRecognizerDirection direction;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_SIDE_SWIPE_GESTURE_RECOGNIZER_H_