Slop region check for multi-finger scroll

ui/events/gesture_detection/gesture_detector.h

 // Copyright 2014 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 UI_EVENTS_GESTURE_DETECTION_GESTURE_DETECTOR_H_
 #define UI_EVENTS_GESTURE_DETECTION_GESTURE_DETECTOR_H_
 
 #include <memory>
 
 #include "base/logging.h"
@@ skipping 92 matching lines @@
   void Init(const Config& config);
   void OnShowPressTimeout();
   void OnLongPressTimeout();
   void OnTapTimeout();
   void Cancel();
   void CancelTaps();
   bool IsRepeatedTap(const MotionEvent& first_down,
                      const MotionEvent& first_up,
                      const MotionEvent& second_down) const;
   bool HandleSwipeIfNeeded(const MotionEvent& up, float vx, float vy);
+  bool IsWithinTouchSlop(const MotionEvent& ev);
 
   class TimeoutGestureHandler;
   std::unique_ptr<TimeoutGestureHandler> timeout_handler_;
   GestureListener* const listener_;
   DoubleTapListener* double_tap_listener_;
 
   float touch_slop_square_;
   float double_tap_touch_slop_square_;
   float double_tap_slop_square_;
   float two_finger_tap_distance_square_;
   float min_fling_velocity_;
   float max_fling_velocity_;
   float min_swipe_velocity_;
   float min_swipe_direction_component_ratio_;
   base::TimeDelta double_tap_timeout_;
   base::TimeDelta two_finger_tap_timeout_;
   base::TimeDelta double_tap_min_time_;
 
   bool still_down_;
   bool defer_confirm_single_tap_;
-  bool always_in_tap_region_;
+  bool all_pointers_within_slop_regions_;
   bool always_in_bigger_tap_region_;
   bool two_finger_tap_allowed_for_gesture_;
 
   std::unique_ptr<MotionEvent> current_down_event_;
   std::unique_ptr<MotionEvent> previous_up_event_;
   std::unique_ptr<MotionEvent> secondary_pointer_down_event_;
 
   // True when the user is still touching for the second tap (down, move, and
   // up events). Can only be true if there is a double tap listener attached.
   bool is_double_tapping_;
 
   // Whether the current ACTION_DOWN event meets the criteria for being a
   // repeated tap. Note that it will be considered a repeated tap only if the
   // corresponding ACTION_UP yields a valid tap and double-tap detection is
   // disabled.
   bool is_down_candidate_for_repeated_single_tap_;
 
+  // Stores the maximum number of pointers that have been down simultaneously
+  // during the current touch sequenece.

[tdresser, 2016/07/01 14:29:15]

sequence 

[sahel, 2016/07/05 20:36:35]

Done.

+  int maximum_pointer_count_;
+
   // The number of repeated taps in the current sequence, i.e., for the initial
   // tap this is 0, for the first *repeated* tap 1, etc...
   int current_single_tap_repeat_count_;
   int single_tap_repeat_interval_;
 
   float last_focus_x_;
   float last_focus_y_;
   float down_focus_x_;
   float down_focus_y_;
 
   bool longpress_enabled_;
   bool showpress_enabled_;
   bool swipe_enabled_;
   bool two_finger_tap_enabled_;
 
   // Determines speed during touch scrolling.
   VelocityTrackerState velocity_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(GestureDetector);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_GESTURE_DETECTION_GESTURE_DETECTOR_H_