Adopt ui::GestureConfiguration on Android

ui/events/gesture_detection/gesture_configuration_android.cc

+// 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.
+
+#include "ui/events/gesture_detection/gesture_configuration.h"
+
+#include "ui/gfx/android/view_configuration.h"
+#include "ui/gfx/screen.h"
+
+using gfx::ViewConfiguration;
+
+namespace ui {
+namespace {
+// This was the minimum tap/press size used on Android before the new gesture
+// detection pipeline.
+const float kMinGestureBoundsLengthDips = 24.f;
+
+// This value is somewhat arbitrary, but provides a reasonable maximum
+// approximating a large thumb depression.
+const float kMaxGestureBoundsLengthDips = kMinGestureBoundsLengthDips * 4.f;
+
+class GestureConfigurationAndroid : public GestureConfiguration {
+ public:
+  static GestureConfigurationAndroid* GetInstance() {
+    return Singleton<GestureConfigurationAndroid>::get();
+  }
+
+ private:
+  GestureConfigurationAndroid() : GestureConfiguration() {
+    float raw_pixel_to_dip_ratio = 1.f / gfx::Screen::GetNativeScreen()
+                                       ->GetPrimaryDisplay()
+                                       .device_scale_factor();
+    set_double_tap_timeout_in_ms(ViewConfiguration::GetDoubleTapTimeoutInMs());
+    set_gesture_begin_end_types_enabled(false);
+    set_long_press_time_in_ms(ViewConfiguration::GetLongPressTimeoutInMs());
+    set_max_distance_between_taps_for_double_tap(
+        ViewConfiguration::GetDoubleTapSlopInPixels() * raw_pixel_to_dip_ratio);
+    set_max_fling_velocity(
+        ViewConfiguration::GetMaximumFlingVelocityInPixelsPerSecond() *
+        raw_pixel_to_dip_ratio);
+    set_max_gesture_bounds_length(kMaxGestureBoundsLengthDips);
+    set_max_touch_move_in_pixels_for_click(
+        ViewConfiguration::GetTouchSlopInPixels() * raw_pixel_to_dip_ratio);
+    set_min_fling_velocity(
+        ViewConfiguration::GetMinimumFlingVelocityInPixelsPerSecond() *
+        raw_pixel_to_dip_ratio);
+    set_min_gesture_bounds_length(kMinGestureBoundsLengthDips);
+    set_min_pinch_update_span_delta(0.f);
+    set_min_scaling_span_in_pixels(
+        ViewConfiguration::GetMinScalingSpanInPixels() *
+        raw_pixel_to_dip_ratio);
+    set_min_scaling_touch_major(
+        ViewConfiguration::GetMinScalingTouchMajorInPixels() *
+        raw_pixel_to_dip_ratio);
+    set_show_press_delay_in_ms(ViewConfiguration::GetTapTimeoutInMs());
+    set_span_slop(ViewConfiguration::GetTouchSlopInPixels() * 2.f *
+                  raw_pixel_to_dip_ratio);
+  }
+
+  friend struct DefaultSingletonTraits<GestureConfigurationAndroid>;
+  DISALLOW_COPY_AND_ASSIGN(GestureConfigurationAndroid);
+};
+
+}  // namespace
+
+GestureConfiguration* GestureConfiguration::GetInstance() {
+  return GestureConfigurationAndroid::GetInstance();

[jdduke (slow), 2014/10/23 20:17:00]

Can this just be Singleton<GestureConfigurationAndroid>::get();?

[lanwei, 2014/10/23 20:50:48]

I tried before, it gave me this error
 error: 'get' is a private member of 'Singleton<ui::(anonymous
namespace)::GestureConfigurationAura, DefaultSingletonTraits<ui::(anonymous
namespace)::GestureConfigurationAura>, ui::(anonymous
namespace)::GestureConfigurationAura>'

I feel it can be only used inside methods in its own class.

+}
+
+}  // namespace ui