Re-enable Eager Gesture Recognition on Aura

ui/aura/window_event_dispatcher.cc

Index: ui/aura/window_event_dispatcher.cc
diff --git a/ui/aura/window_event_dispatcher.cc b/ui/aura/window_event_dispatcher.cc
index 0b1103d016880e8015092b7a734b0a5145a34acc..8980b5f330e2283a7f0ef154f91004a2a66626d8 100644
--- a/ui/aura/window_event_dispatcher.cc
+++ b/ui/aura/window_event_dispatcher.cc
@@ -159,18 +159,11 @@ DispatchDetails WindowEventDispatcher::DispatchMouseExitAtPoint(
 void WindowEventDispatcher::ProcessedTouchEvent(ui::TouchEvent* event,
                                                 Window* window,
                                                 ui::EventResult result) {
-  // TODO(tdresser): Move this to PreDispatchTouchEvent, to enable eager
-  // gesture detection. See crbug.com/410280.
-  if (!ui::GestureRecognizer::Get()
-           ->ProcessTouchEventPreDispatch(*event, window)) {
-    return;
-  }
-
   // Once we've fully migrated to the eager gesture detector, we won't need to
   // pass an event here.
   scoped_ptr<ui::GestureRecognizer::Gestures> gestures(
-      ui::GestureRecognizer::Get()->ProcessTouchEventOnAsyncAck(
-          *event, result, window));
+      ui::GestureRecognizer::Get()
+          ->ProcessTouchEventAck(*event, result, window));
   DispatchDetails details = ProcessGestures(gestures.get());
   if (details.dispatcher_destroyed)
     return;
@@ -497,6 +490,10 @@ ui::EventDispatchDetails WindowEventDispatcher::PostDispatchEvent(
     // being dispatched.
     if (dispatching_held_event_ || !held_move_event_ ||
         !held_move_event_->IsTouchEvent()) {
+      // If the event is being handled asynchronously, ignore it.
+      if(event.result() & ui::ER_CONSUMED)
+        return details;
+      scoped_ptr<ui::GestureRecognizer::Gestures> gestures;
 
       // Once we've fully migrated to the eager gesture detector, we won't
       // need to pass an event here.
@@ -504,30 +501,31 @@ ui::EventDispatchDetails WindowEventDispatcher::PostDispatchEvent(
                                 static_cast<Window*>(event.target()),
                                 window());
 
-      if (event.result() & ui::ER_CONSUMED)
-        orig_event.StopPropagation();
-
-      // TODO(tdresser): Move this to PreDispatchTouchEvent, to enable eager
-      // gesture detection. See crbug.com/410280.
-      if (!ui::GestureRecognizer::Get()
-               ->ProcessTouchEventPreDispatch(orig_event,
-                                              static_cast<Window*>(target))) {
-        return details;
+      if (ui::GestureRecognizer::Get()->ProcessTouchEvent(
+              orig_event, static_cast<Window*>(target))) {
+        gestures.reset(ui::GestureRecognizer::Get()->ProcessTouchEventAck(
+            orig_event, event.result(), static_cast<Window*>(target)));
+        return ProcessGestures(gestures.get());
       }
-
-      scoped_ptr<ui::GestureRecognizer::Gestures> gestures;
-
-      gestures.reset(
-          ui::GestureRecognizer::Get()->ProcessTouchEventPostDispatch(
-              orig_event, event.result(), static_cast<Window*>(target)));
-
-      return ProcessGestures(gestures.get());
     }
   }
 
   return details;
 }
 
+bool WindowEventDispatcher::OnForwardingAsyncTouchEvent(ui::TouchEvent* event) {
+  ui::TouchEvent orig_event(
+      *event, static_cast<aura::Window*>(event->target()), window());
+
+  bool should_forward = ui::GestureRecognizer::Get()->ProcessTouchEvent(
+      orig_event, static_cast<aura::Window*>(event->target()));
+
+  // Make sure that |PostDispatch| doesn't give |event| to the GestureRecognizer
+  // again.
+  event->StopPropagation();
+  return should_forward;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // WindowEventDispatcher, ui::GestureEventHelper implementation: