Expose double-tap platform support via ui::GestureConfiguration

ui/events/gesture_detection/gesture_configuration.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_CONFIGURATION_H_
 #define UI_EVENTS_GESTURE_DETECTION_GESTURE_CONFIGURATION_H_
 
 #include "base/basictypes.h"
 #include "base/memory/singleton.h"
 #include "ui/events/gesture_detection/gesture_detection_export.h"
 #include "ui/events/gesture_detection/velocity_tracker.h"
 
 namespace ui {
 
 class GESTURE_DETECTION_EXPORT GestureConfiguration {
  public:
   // Returns the singleton GestureConfiguration.
   static GestureConfiguration* GetInstance();
 
   // Ordered alphabetically ignoring underscores.
   float default_radius() const { return default_radius_; }
   void set_default_radius(float radius) {
     default_radius_ = radius;
     min_scaling_touch_major_ = default_radius_ * 2;
     min_gesture_bounds_length_ = default_radius_;
   }
+  bool double_tap_enabled() const { return double_tap_enabled_; }
+  void set_double_tap_enabled(bool enabled) { double_tap_enabled_ = enabled; }
   int double_tap_timeout_in_ms() const { return double_tap_timeout_in_ms_; }
   int fling_max_cancel_to_down_time_in_ms() const {
     return fling_max_cancel_to_down_time_in_ms_;
   }
   void set_fling_max_cancel_to_down_time_in_ms(int val) {
     fling_max_cancel_to_down_time_in_ms_ = val;
   }
   int fling_max_tap_gap_time_in_ms() const {
     return fling_max_tap_gap_time_in_ms_;
   }
@@ skipping 141 matching lines @@
   void set_span_slop(float val) { span_slop_ = val; }
 
  private:
   // These are listed in alphabetical order ignoring underscores.
   // NOTE: Adding new configuration parameters requires initializing
   // corresponding entries in aura_test_base.cc's SetUp().
 
   // The default touch radius length used when the only information given
   // by the device is the touch center.
   float default_radius_;
+
+  bool double_tap_enabled_;
   int double_tap_timeout_in_ms_;
+
   // Maximum time between a GestureFlingCancel and a mousedown such that the
   // mousedown is considered associated with the cancel event.
   int fling_max_cancel_to_down_time_in_ms_;
 
   // Maxium time between a mousedown/mouseup pair that is considered to be a
   // suppressable tap.
   int fling_max_tap_gap_time_in_ms_;
   bool gesture_begin_end_types_enabled_;
   int long_press_time_in_ms_;
   float max_distance_between_taps_for_double_tap_;
@@ skipping 28 matching lines @@
   bool two_finger_tap_enabled_;
   VelocityTracker::Strategy velocity_tracker_strategy_;
 
   friend struct DefaultSingletonTraits<GestureConfiguration>;
   DISALLOW_COPY_AND_ASSIGN(GestureConfiguration);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_GESTURE_DETECTION_GESTURE_CONFIGURATION_H_