[Android] Support double-tap selection

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 "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/events/gesture_detection/gesture_detection_export.h"
@@ skipping 51 matching lines @@
     // Whether |OnTwoFingerTap| should be called for two finger tap
     // gestures. Defaults to false.
     bool two_finger_tap_enabled;
 
     // Maximum distance between pointers for a two finger tap.
     float two_finger_tap_max_separation;
 
     // Maximum time the second pointer can be active for a two finger tap.
     base::TimeDelta two_finger_tap_timeout;
 
+    // Single tap count repetition length. Defaults to 1 (no repetition count).
+    // Note that when double-tap detection is enabled, the single tap repeat
+    // count will always be 1.
+    int single_tap_repeat_interval;
+
     VelocityTracker::Strategy velocity_tracker_strategy;
   };
 
   GestureDetector(const Config& config,
                   GestureListener* listener,
                   DoubleTapListener* optional_double_tap_listener);
   ~GestureDetector();
 
   bool OnTouchEvent(const MotionEvent& ev);
 
   // Setting a valid |double_tap_listener| will enable double-tap detection,
   // wherein calls to |OnSimpleTapConfirmed| are delayed by the tap timeout.
   // Note: The listener must never be changed while |is_double_tapping| is true.
   void SetDoubleTapListener(DoubleTapListener* double_tap_listener);
 
   bool has_doubletap_listener() const { return double_tap_listener_ != NULL; }
 
   bool is_double_tapping() const { return is_double_tapping_; }
 
   void set_longpress_enabled(bool enabled) { longpress_enabled_ = enabled; }
   void set_showpress_enabled(bool enabled) { showpress_enabled_ = enabled; }
 
  private:
   void Init(const Config& config);
   void OnShowPressTimeout();
   void OnLongPressTimeout();
   void OnTapTimeout();
   void Cancel();
   void CancelTaps();
-  bool IsConsideredDoubleTap(const MotionEvent& first_down,
-                             const MotionEvent& first_up,
-                             const MotionEvent& second_down) const;
+  bool IsRepeatedTap(const MotionEvent& first_down,
+                     const MotionEvent& first_up,
+                     const MotionEvent& second_down) const;
   bool HandleSwipeIfNeeded(const MotionEvent& up, float vx, float vy);
 
   class TimeoutGestureHandler;
   scoped_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_;
@@ skipping 13 matching lines @@
   bool two_finger_tap_allowed_for_gesture_;
 
   scoped_ptr<MotionEvent> current_down_event_;
   scoped_ptr<MotionEvent> previous_up_event_;
   scoped_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_;
+
+  // 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_