Re-enable Eager Gesture Recognition on Aura

ui/events/gesture_detection/gesture_event_data_packet.cc

Index: ui/events/gesture_detection/gesture_event_data_packet.cc
diff --git a/ui/events/gesture_detection/gesture_event_data_packet.cc b/ui/events/gesture_detection/gesture_event_data_packet.cc
index 265300cc1fcdfb7bf0c137ce0e2d09b7790b464c..375225f42c1dd097715f2b624897eb2eaa1983c2 100644
--- a/ui/events/gesture_detection/gesture_event_data_packet.cc
+++ b/ui/events/gesture_detection/gesture_event_data_packet.cc
@@ -33,7 +33,7 @@ GestureEventDataPacket::GestureSource ToGestureSource(
 }  // namespace
 
 GestureEventDataPacket::GestureEventDataPacket()
-    : gesture_source_(UNDEFINED) {
+    : gesture_source_(UNDEFINED), ack_state_(AckState::PENDING) {
 }
 
 GestureEventDataPacket::GestureEventDataPacket(
@@ -44,7 +44,8 @@ GestureEventDataPacket::GestureEventDataPacket(
     : timestamp_(timestamp),
       touch_location_(touch_location),
       raw_touch_location_(raw_touch_location),
-      gesture_source_(source) {
+      gesture_source_(source),
+      ack_state_(AckState::PENDING) {
   DCHECK_NE(gesture_source_, UNDEFINED);
 }
 
@@ -54,7 +55,8 @@ GestureEventDataPacket::GestureEventDataPacket(
       gestures_(other.gestures_),
       touch_location_(other.touch_location_),
       raw_touch_location_(other.raw_touch_location_),
-      gesture_source_(other.gesture_source_) {
+      gesture_source_(other.gesture_source_),
+      ack_state_(AckState::PENDING) {
 }
 
 GestureEventDataPacket::~GestureEventDataPacket() {
@@ -67,6 +69,7 @@ GestureEventDataPacket& GestureEventDataPacket::operator=(
   touch_location_ = other.touch_location_;
   raw_touch_location_ = other.raw_touch_location_;
   gestures_ = other.gestures_;
+  ack_state_ = other.ack_state_;
   return *this;
 }
 
@@ -93,4 +96,8 @@ GestureEventDataPacket GestureEventDataPacket::FromTouchTimeout(
   return packet;
 }
 
+void GestureEventDataPacket::ack(bool event_consumed) {
+  ack_state_ = event_consumed ? AckState::CONSUMED : AckState::UNCONSUMED;

[jdduke (slow), 2014/11/26 16:07:09]

maybe |DCHECK_EQ(ack_state_, AckState::PENDING)|.

[tdresser, 2014/11/27 18:26:24]

We explicitly allow spurious acks, so to add that check here I'd have to add
some additional guards elsewhere.

Otherwise I can add some comments indicating why we don't have those checks
here.
What do you think?

[jdduke (slow), 2014/12/02 16:21:59]

Some kind of check would be nice, e.g., can we at least verify that it hasn't
been consumed already?

[tdresser, 2014/12/02 21:29:27]

The renderer could send us spurious event consumed acks, couldn't it?

[jdduke (slow), 2014/12/02 21:34:03]

Hmm, but the spurious ack from the renderer should always be async, in which
case the queue should either be empty or we'll be ack'ing an event that's never
been ack'ed (events that may have been ack'ed synchrously would have been
dispatched already).

[tdresser, 2014/12/02 22:00:22]

Good point.
Done.

+}
+
 }  // namespace ui