Expose double-tap platform support via ui::GestureConfiguration

ui/events/gesture_detection/gesture_provider.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_PROVIDER_H_
 #define UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/events/gesture_detection/gesture_detection_export.h"
@@ skipping 23 matching lines @@
     GestureDetector::Config gesture_detector_config;
     ScaleGestureDetector::Config scale_gesture_detector_config;
 
     // If |disable_click_delay| is true and double-tap support is disabled,
     // there will be no delay before tap events. When double-tap support is
     // enabled, there will always be a delay before a tap event is fired, in
     // order to allow the double tap gesture to occur without firing any tap
     // events.
     bool disable_click_delay;
 
+    // Whether double-tap detection is supported by the platform. If disabled,
+    // there will be no delay before tap events. Defaults to true.
+    bool double_tap_support_for_platform_enabled;
+
     // If |gesture_begin_end_types_enabled| is true, fire an ET_GESTURE_BEGIN
     // event for every added touch point, and an ET_GESTURE_END event for every
     // removed touch point. This requires one ACTION_CANCEL event to be sent per
     // touch point, which only occurs on Aura. Defaults to false.
     bool gesture_begin_end_types_enabled;
 
     // The min and max size (both length and width, in dips) of the generated
     // bounding box for all gesture types. This is useful for touch streams
     // that may report zero or unreasonably small or large touch sizes.
     // Note that these bounds are only applied for touch or unknown tool types;
@@ skipping 59 matching lines @@
   // Whether double-tap gesture detection is currently supported.
   bool double_tap_support_for_page_;
   bool double_tap_support_for_platform_;
 
   const bool gesture_begin_end_types_enabled_;
 };
 
 }  //  namespace ui
 
 #endif  // UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_