Routes touch ACK events to the correct GestureProvider

ui/events/gestures/gesture_recognizer_impl.cc

Index: ui/events/gestures/gesture_recognizer_impl.cc
diff --git a/ui/events/gestures/gesture_recognizer_impl.cc b/ui/events/gestures/gesture_recognizer_impl.cc
index 206ef82c178bf176cb6c3c40ecc5edf0ed95f2e8..7ea6660879a7b9668335d45a9109d1277aa7c8ad 100644
--- a/ui/events/gestures/gesture_recognizer_impl.cc
+++ b/ui/events/gestures/gesture_recognizer_impl.cc
@@ -273,6 +273,7 @@ bool GestureRecognizerImpl::ProcessTouchEventPreDispatch(
 
   GestureProviderAura* gesture_provider =
       GetGestureProviderForConsumer(consumer);
+  event_to_gesture_provider_[event->unique_event_id()] = gesture_provider;

[tdresser, 2017/04/06 20:59:52]

Can we put this in SetupTargets?

[malaykeshav, 2017/04/07 01:07:59]

Done

   return gesture_provider->OnTouchEvent(event);
 }
 
@@ -280,8 +281,16 @@ GestureRecognizer::Gestures GestureRecognizerImpl::AckTouchEvent(
     uint32_t unique_event_id,
     ui::EventResult result,
     GestureConsumer* consumer) {
-  GestureProviderAura* gesture_provider =
-      GetGestureProviderForConsumer(consumer);
+  GestureProviderAura* gesture_provider = nullptr;
+
+  // Check if we have already processed this event before dispatch and have a
+  // consumer associated with it.
+  if (event_to_gesture_provider_.count(unique_event_id)) {
+    gesture_provider = event_to_gesture_provider_[unique_event_id];
+    event_to_gesture_provider_.erase(unique_event_id);

[tdresser, 2017/04/06 20:59:52]

This is performing three lookups into this map.

How about something along the lines of:

auto event_to_gesture_provider_iterator =
event_to_gesture_provider_.find(unique_event_id)
if (event_to_gesture_provider_iterator != event_to_gesture_provider_.end()) {
     gesture_provider = *event_to_gesture_provider_iterator;
     event_to_gesture_provider_.erase(event_to_gesture_provider_iterator);
}

This only does a single index into the map.

[malaykeshav, 2017/04/07 01:07:59]

Done

+  } else {
+    gesture_provider = GetGestureProviderForConsumer(consumer);
+  }
   gesture_provider->OnTouchEventAck(unique_event_id, result != ER_UNHANDLED);
   return gesture_provider->GetAndResetPendingGestures();
 }