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

ios/chrome/browser/ui/stack_view/card_stack_pinch_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_STACK_VIEW_CARD_STACK_PINCH_GESTURE_RECOGNIZER_H_
+#define IOS_CHROME_BROWSER_UI_STACK_VIEW_CARD_STACK_PINCH_GESTURE_RECOGNIZER_H_
+
+#import <UIKit/UIGestureRecognizerSubclass.h>
+#import <UIKit/UIKit.h>
+
+// This gesture recognizer maintains state of the pinch with greater detail
+// than is available via the interface of a stock UIPinchGestureRecognizer.
+@interface CardStackPinchGestureRecognizer : UIPinchGestureRecognizer {
+}
+
+// Number of non-cancelled, non-ended touches involved in the gesture.
+@property(nonatomic, readonly) NSUInteger numberOfActiveTouches;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_STACK_VIEW_CARD_STACK_PINCH_GESTURE_RECOGNIZER_H_