Support GestureBegin and GestureEnd in ui::GestureProvider

ui/events/gesture_detection/gesture_provider.cc

Index: ui/events/gesture_detection/gesture_provider.cc
diff --git a/ui/events/gesture_detection/gesture_provider.cc b/ui/events/gesture_detection/gesture_provider.cc
index 4deeba2580f3a7a72928cd3cec30f4a401aa2f18..4e0516a3cf04d44dccb676d83808e63bb3e43bb1 100644
--- a/ui/events/gesture_detection/gesture_provider.cc
+++ b/ui/events/gesture_detection/gesture_provider.cc
@@ -76,7 +76,8 @@ GestureEventDetails CreateTapGestureDetails(EventType type,
 
 // GestureProvider:::Config
 
-GestureProvider::Config::Config() : disable_click_delay(false) {}
+GestureProvider::Config::Config()
+    : disable_click_delay(false), send_aura_specific_gestures(false) {}
 
 GestureProvider::Config::~Config() {}
 
@@ -604,7 +605,8 @@ GestureProvider::GestureProvider(const Config& config,
       needs_show_press_event_(false),
       needs_tap_ending_event_(false),
       touch_scroll_in_progress_(false),
-      pinch_in_progress_(false) {
+      pinch_in_progress_(false),
+      send_aura_specific_gestures_(false) {
   DCHECK(client);
   InitGestureDetectors(config);
 }
@@ -617,6 +619,9 @@ bool GestureProvider::OnTouchEvent(const MotionEvent& event) {
   if (!CanHandle(event))
     return false;
 
+  if (send_aura_specific_gestures_)
+    SendGestureBeginOrEndIfNecessary(event);

[jdduke (slow), 2014/04/03 20:17:16]

But don't we want the GestureEnd to come after events that might be generated by
the ACTION_UP or ACTION_POINTER_UP?  I think you'l need to have a call before
handling and after handling.

Ideally, we'd move code that comes before into a |OnTouchEventHandlingBegin(e)|,
and that would also do the ACTION_DOWN stuff below.  Then we'd have a
|OnTouchEventHandlingEnd(e)|, doing the ACTION_UP/ACTION_CANCEL cleanup (in
addition to the begin/end sending).

[tdresser, 2014/04/03 21:14:41]

Done.

+
   const bool was_touch_scrolling_ = touch_scroll_in_progress_;
   const bool in_scale_gesture =
       scale_gesture_listener_->IsScaleGestureDetectionInProgress();
@@ -696,6 +701,7 @@ void GestureProvider::InitGestureDetectors(const Config& config) {
 
   scale_gesture_listener_.reset(
       new ScaleGestureListenerImpl(config.scale_gesture_detector_config, this));
+  send_aura_specific_gestures_ = config.send_aura_specific_gestures;
 }
 
 bool GestureProvider::CanHandle(const MotionEvent& event) const {
@@ -734,7 +740,8 @@ void GestureProvider::Send(const GestureEventData& gesture) {
   // 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_BEGIN);
 
   switch (gesture.type) {
     case ET_GESTURE_TAP_DOWN:
@@ -818,4 +825,21 @@ void GestureProvider::EndTouchScrollIfNecessary(base::TimeTicks time,
     Send(CreateGesture(ET_GESTURE_SCROLL_END, time, 0, 0));
 }
 
+void GestureProvider::SendGestureBeginOrEndIfNecessary(
+    const MotionEvent& event) {
+  switch(event.GetAction()) {

[jdduke (slow), 2014/04/03 20:17:16]

Might as well move the check for the condition here, i.e., |if
(!gesture_begin_end_enabled_) return|, and just always call this depending on
the action.

[tdresser, 2014/04/03 21:14:41]

Done.

+    case MotionEvent::ACTION_DOWN:
+    case MotionEvent::ACTION_POINTER_DOWN:
+      Send(CreateGesture(ET_GESTURE_BEGIN, event));
+      break;
+    case MotionEvent::ACTION_UP:
+    case MotionEvent::ACTION_POINTER_UP:
+    case MotionEvent::ACTION_CANCEL:
+      Send(CreateGesture(ET_GESTURE_END, event));
+      break;
+    case MotionEvent::ACTION_MOVE:
+      break;
+  }
+}
+
 }  //  namespace ui