Sync ui/events to chromium @ https://codereview.chromium.org/1210203002

ui/events/gesture_detection/gesture_detector.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.
 
 // MSVC++ requires this to be set before any other includes to get M_PI.
 #define _USE_MATH_DEFINES
 
 #include "ui/events/gesture_detection/gesture_detector.h"
 
 #include <cmath>
@@ skipping 20 matching lines @@
 enum TimeoutEvent {
   SHOW_PRESS = 0,
   LONG_PRESS,
   TAP,
   TIMEOUT_EVENT_COUNT
 };
 
 }  // namespace
 
 // Note: These constants were taken directly from the default (unscaled)
-// versions found in Android's ViewConfiguration.
+// versions found in Android's ViewConfiguration. Do not change these default
+// values without explicitly consulting an OWNER.
 GestureDetector::Config::Config()
     : longpress_timeout(base::TimeDelta::FromMilliseconds(500)),
       showpress_timeout(base::TimeDelta::FromMilliseconds(180)),
       double_tap_timeout(base::TimeDelta::FromMilliseconds(300)),
       double_tap_min_time(base::TimeDelta::FromMilliseconds(40)),
       touch_slop(8),
       double_tap_slop(100),
       minimum_fling_velocity(50),
       maximum_fling_velocity(8000),
       swipe_enabled(false),
       minimum_swipe_velocity(20),
       maximum_swipe_deviation_angle(20.f),
       two_finger_tap_enabled(false),
       two_finger_tap_max_separation(300),
-      two_finger_tap_timeout(base::TimeDelta::FromMilliseconds(700)) {
+      two_finger_tap_timeout(base::TimeDelta::FromMilliseconds(700)),
+      velocity_tracker_strategy(VelocityTracker::Strategy::STRATEGY_DEFAULT) {
 }
 
 GestureDetector::Config::~Config() {}
 
 class GestureDetector::TimeoutGestureHandler {
  public:
   TimeoutGestureHandler(const Config& config, GestureDetector* gesture_detector)
       : gesture_detector_(gesture_detector) {
     DCHECK(config.showpress_timeout <= config.longpress_timeout);
 
@@ skipping 60 matching lines @@
       always_in_bigger_tap_region_(false),
       two_finger_tap_allowed_for_gesture_(false),
       is_double_tapping_(false),
       last_focus_x_(0),
       last_focus_y_(0),
       down_focus_x_(0),
       down_focus_y_(0),
       longpress_enabled_(true),
       showpress_enabled_(true),
       swipe_enabled_(false),
-      two_finger_tap_enabled_(false) {
+      two_finger_tap_enabled_(false),
+      velocity_tracker_(config.velocity_tracker_strategy) {
   DCHECK(listener_);
   Init(config);
 }
 
 GestureDetector::~GestureDetector() {}
 
 bool GestureDetector::OnTouchEvent(const MotionEvent& ev) {
   const MotionEvent::Action action = ev.GetAction();
 
   velocity_tracker_.AddMovement(ev);
@@ skipping 137 matching lines @@
                 *current_down_event_, ev, scroll_x, scroll_y);
             last_focus_x_ = focus_x;
             last_focus_y_ = focus_y;
             always_in_tap_region_ = false;
             timeout_handler_->Stop();
           }
           if (distance_square > double_tap_touch_slop_square_)
             always_in_bigger_tap_region_ = false;
         } else if (std::abs(scroll_x) > kScrollEpsilon ||
                    std::abs(scroll_y) > kScrollEpsilon) {
+          // We should eventually apply touch slop for multi-finger
+          // scrolls as well as single finger scrolls. See
+          // crbug.com/492185 for details.
           handled =
               listener_->OnScroll(*current_down_event_, ev, scroll_x, scroll_y);
           last_focus_x_ = focus_x;
           last_focus_y_ = focus_y;
         }
 
         if (!two_finger_tap_allowed_for_gesture_)
           break;
 
         // Two-finger tap should be prevented if either pointer exceeds its
@@ skipping 121 matching lines @@
 
 void GestureDetector::OnLongPressTimeout() {
   timeout_handler_->StopTimeout(TAP);
   defer_confirm_single_tap_ = false;
   listener_->OnLongPress(*current_down_event_);
 }
 
 void GestureDetector::OnTapTimeout() {
   if (!double_tap_listener_)
     return;
-  if (!still_down_)
-    double_tap_listener_->OnSingleTapConfirmed(*current_down_event_);
-  else
+  if (!still_down_) {
+    CHECK(previous_up_event_);
+    double_tap_listener_->OnSingleTapConfirmed(*previous_up_event_);
+  } else {
     defer_confirm_single_tap_ = true;
+  }
 }
 
 void GestureDetector::Cancel() {
   CancelTaps();
   velocity_tracker_.Clear();
   still_down_ = false;
 }
 
 void GestureDetector::CancelTaps() {
   timeout_handler_->Stop();
@@ skipping 41 matching lines @@
     return false;
 
   if (vx_abs > vy_abs)
     vy = 0;
   else
     vx = 0;
   return listener_->OnSwipe(*current_down_event_, up, vx, vy);
 }
 
 }  // namespace ui