Adopt ui::GestureConfiguration on Android

ui/events/gesture_detection/gesture_configuration_aura.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 <cmath>
+
+namespace ui {
+
+namespace {
+
+class GESTURE_DETECTION_EXPORT GestureConfigurationAura
+    : public GestureConfiguration {
+ public:
+  static GestureConfigurationAura* GetInstance() {
+    return Singleton<GestureConfigurationAura>::get();
+  }
+
+ private:
+  GestureConfigurationAura() : GestureConfiguration() {
+    set_fling_velocity_cap(17000.0f);
+    set_gesture_begin_end_types_enabled(true);
+    set_long_press_time_in_ms(1000);
+    set_max_distance_between_taps_for_double_tap(20);
+    set_max_touch_move_in_pixels_for_click(15);
+    // Half the size of the default touch length is a reasonable minimum.
+    set_min_gesture_bounds_length(default_radius());
+    set_min_pinch_update_span_delta(
+        CommandLine::ForCurrentProcess()->HasSwitch(
+            switches::kCompensateForUnstablePinchZoom)
+            ? min_pinch_update_distance_in_pixels()
+            : 0);
+    // If this is too small, we currently can get single finger pinch zoom. See
+    // crbug.com/357237 for details.
+    set_min_scaling_span_in_pixels(125);
+    set_min_scaling_touch_major(default_radius() * 2);
+    set_min_scroll_velocity(30.0f);
+    set_semi_long_press_time_in_ms(400);
+    set_show_press_delay_in_ms(150);
+    set_span_slop(max_touch_move_in_pixels_for_click() * 2);
+    set_swipe_enabled(true);
+    set_two_finger_tap_enabled(true);
+    gfx::Screen* screen = gfx::Screen::GetScreenByType(gfx::SCREEN_TYPE_NATIVE);
+    // |screen| is sometimes NULL during tests.
+    if (screen)
+      set_display(screen->GetPrimaryDisplay());
+  }
+  friend struct DefaultSingletonTraits<GestureConfigurationAura>;
+  DISALLOW_COPY_AND_ASSIGN(GestureConfigurationAura);
+};

[tdresser, 2014/10/22 17:25:18]

We use a comment to indicate ending namespaces, and put a blank line above the
brace.

"}  // namespace"

[lanwei, 2014/10/23 01:26:18]

Done.

+}
+
+GestureConfiguration* GestureConfiguration::GetInstance() {
+  return GestureConfigurationAura::GetInstance();
+}
+
+GestureProvider::Config DefaultGestureProviderConfig() {
+  return GestureConfigurationAura::GetInstance()
+      ->DefaultGestureProviderConfig();
+}
+
+}  // namespace ui