Eager Gesture Recognition on Aura

ui/events/gesture_detection/gesture_provider.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_provider.h"
 
 #include <cmath>
 
 #include "base/auto_reset.h"
 #include "base/debug/trace_event.h"
@@ skipping 621 matching lines @@
                               config.disable_click_delay,
                               this));
 
   scale_gesture_listener_.reset(
       new ScaleGestureListenerImpl(config.scale_gesture_detector_config, this));
 
   UpdateDoubleTapDetectionSupport();
 }
 
 bool GestureProvider::CanHandle(const MotionEvent& event) const {
-  return event.GetAction() == MotionEvent::ACTION_DOWN || current_down_event_;
+  // Aura requires one cancel event per touch point, whereas Android requires
+  // one cancel event per touch sequence. Thus we need to allow extra cancel
+  // events.
+  return event.GetAction() == MotionEvent::ACTION_DOWN || current_down_event_ ||
+         event.GetAction() == MotionEvent::ACTION_CANCEL;
 }
 
 void GestureProvider::Fling(const MotionEvent& event,
                             float velocity_x,
                             float velocity_y) {
   if (!velocity_x && !velocity_y) {
     EndTouchScrollIfNecessary(event, true);
     return;
   }
 
@@ skipping 12 matching lines @@
       ET_SCROLL_FLING_START, velocity_x, velocity_y);
   Send(CreateGesture(fling_details, event));
 }
 
 void GestureProvider::Send(GestureEventData gesture) {
   DCHECK(!gesture.time.is_null());
   // The only valid events that should be sent without an active touch sequence
   // are SHOW_PRESS and TAP, potentially triggered by the double-tap
   // delay timing out.
   DCHECK(current_down_event_ || gesture.type() == ET_GESTURE_TAP ||
-         gesture.type() == ET_GESTURE_SHOW_PRESS);
+         gesture.type() == ET_GESTURE_SHOW_PRESS ||
+         gesture.type() == ET_GESTURE_END);
 
   // TODO(jdduke): Provide a way of skipping this clamping for stylus and/or
   // mouse-based input, perhaps by exposing the source type on MotionEvent.
   gesture.details.set_bounding_box(
       ClampBoundingBox(gesture.details.bounding_box_f(),
                        min_gesture_bounds_length_,
                        max_gesture_bounds_length_));
 
   switch (gesture.type()) {
     case ET_GESTURE_LONG_PRESS:
@@ skipping 89 matching lines @@
 }
 
 void GestureProvider::OnTouchEventHandlingEnd(const MotionEvent& event) {
   switch (event.GetAction()) {
     case MotionEvent::ACTION_UP:
     case MotionEvent::ACTION_CANCEL: {
       // Note: This call will have no effect if a fling was just generated, as
       // |Fling()| will have already signalled an end to touch-scrolling.
       EndTouchScrollIfNecessary(event, true);
 
-      const gfx::RectF bounding_box = GetBoundingBox(event);
-
-      if (gesture_begin_end_types_enabled_) {
-        for (size_t i = 0; i < event.GetPointerCount(); ++i) {
-          Send(CreateGesture(ET_GESTURE_END,
-                             event.GetId(),
-                             event.GetEventTime(),
-                             event.GetX(i),
-                             event.GetY(i),
-                             event.GetRawX(i),
-                             event.GetRawY(i),
-                             event.GetPointerCount() - i,
-                             bounding_box));
-        }
-      }
+      if (gesture_begin_end_types_enabled_)
+        Send(CreateGesture(ET_GESTURE_END, event));
 
       current_down_event_.reset();
 
       UpdateDoubleTapDetectionSupport();
       break;
     }
     case MotionEvent::ACTION_POINTER_UP:
       if (gesture_begin_end_types_enabled_)
         Send(CreateGesture(ET_GESTURE_END, event));
       break;
@@ skipping 11 matching lines @@
   if (current_down_event_)
     return;
 
   const bool double_tap_enabled = double_tap_support_for_page_ &&
                                   double_tap_support_for_platform_;
   gesture_listener_->SetDoubleTapEnabled(double_tap_enabled);
   scale_gesture_listener_->SetDoubleTapEnabled(double_tap_enabled);
 }
 
 }  //  namespace ui