Eager Gesture Recognition on Aura

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 38c07f8ecacd6d06debe667e77c9ae5a40de563e..099d29f0112973af828b491cf255fe71110afd45 100644
--- a/ui/events/gestures/gesture_recognizer_impl.cc
+++ b/ui/events/gestures/gesture_recognizer_impl.cc
@@ -288,26 +288,54 @@ void GestureRecognizerImpl::DispatchGestureEvent(GestureEvent* event) {
   }
 }
 
-ScopedVector<GestureEvent>* GestureRecognizerImpl::ProcessTouchEventForGesture(
+bool GestureRecognizerImpl::ProcessTouchEventPreDispatch(
     const TouchEvent& event,
-    ui::EventResult result,
-    GestureConsumer* target) {
-  SetupTargets(event, target);
+    GestureConsumer* consumer) {
+  SetupTargets(event, consumer);

[sadrul, 2014/08/06 00:46:08]

I think this is a slight change in behaviour: we currently set the target after
the touch-event has been dispatched. With this change, we set the target before
the touch-event has been dispatched. This can break if, for example, there are
nested event-dispatch. I can't think of an actual case where this may be a
problem, but we should keep any eye on this for incoming bugs.

[tdresser, 2014/08/06 12:47:04]

Hmmm, good thought. I'll keep it in mind.

 
-  if (!use_unified_gesture_detector_) {
-    GestureSequence* gesture_sequence = GetGestureSequenceForConsumer(target);
-    return gesture_sequence->ProcessTouchEventForGesture(event, result);
+  // If we aren't using the unified GR, we definitely want to dispatch the
+  // event.
+  if (!ui::IsUnifiedGestureDetectorEnabled())
+    return true;
+
+  if (event.result() & ER_CONSUMED)
+    return false;
+
+  GestureProviderAura* gesture_provider =
+      GetGestureProviderForConsumer(consumer);
+  return gesture_provider->OnTouchEvent(event);
+}
+
+GestureRecognizer::Gestures*
+GestureRecognizerImpl::ProcessTouchEventPostDispatch(
+    const TouchEvent& event,
+    ui::EventResult result,
+    GestureConsumer* consumer) {
+  if (ui::IsUnifiedGestureDetectorEnabled()) {
+    GestureProviderAura* gesture_provider =
+        GetGestureProviderForConsumer(consumer);
+    gesture_provider->OnTouchEventAck(result != ER_UNHANDLED);
+    return gesture_provider->GetAndResetPendingGestures();
   } else {
+    GestureSequence* gesture_sequence = GetGestureSequenceForConsumer(consumer);
+    return gesture_sequence->ProcessTouchEventForGesture(event, result);
+  }
+}
+
+GestureRecognizer::Gestures* GestureRecognizerImpl::ProcessTouchEventOnAsyncAck(
+    const TouchEvent& event,
+    ui::EventResult result,
+    GestureConsumer* consumer) {
+  if (ui::IsUnifiedGestureDetectorEnabled()) {
+    if (result & ui::ER_CONSUMED)
+      return NULL;
     GestureProviderAura* gesture_provider =
-        GetGestureProviderForConsumer(target);
-    // TODO(tdresser) - detect gestures eagerly.
-    if (!(result & ER_CONSUMED)) {
-      if (gesture_provider->OnTouchEvent(event)) {
-        gesture_provider->OnTouchEventAck(result != ER_UNHANDLED);
-        return gesture_provider->GetAndResetPendingGestures();
-      }
-    }
-    return NULL;
+        GetGestureProviderForConsumer(consumer);
+    gesture_provider->OnTouchEventAck(result != ER_UNHANDLED);
+    return gesture_provider->GetAndResetPendingGestures();
+  } else {
+    GestureSequence* gesture_sequence = GetGestureSequenceForConsumer(consumer);
+    return gesture_sequence->ProcessTouchEventForGesture(event, result);
   }
 }