Routes touch ACK events to the correct GestureProvider

ui/events/gestures/gesture_recognizer_impl.cc

 // Copyright (c) 2012 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/gestures/gesture_recognizer_impl.h"
 
 #include <stddef.h>
 
 #include <limits>
 #include <memory>
@@ skipping 255 matching lines @@
 bool GestureRecognizerImpl::ProcessTouchEventPreDispatch(
     TouchEvent* event,
     GestureConsumer* consumer) {
   SetupTargets(*event, consumer);
 
   if (event->result() & ER_CONSUMED)
     return false;
 
   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);
 }
 
 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();
 }
 
 bool GestureRecognizerImpl::CleanupStateForConsumer(
     GestureConsumer* consumer) {
   bool state_cleaned_up = false;
 
   if (consumer_gesture_provider_.count(consumer)) {
     state_cleaned_up = true;
@@ skipping 58 matching lines @@
   std::vector<GestureEventHelper*>::iterator it;
   for (it = helpers.begin(); it != helpers.end(); ++it)
     gesture_recognizer->AddGestureEventHelper(*it);
 
   helpers.clear();
   g_gesture_recognizer_instance =
       static_cast<GestureRecognizerImpl*>(gesture_recognizer);
 }
 
 }  // namespace ui