aura: Start converting event-filters into event-handlers.

ui/aura/root_window.cc

Index: ui/aura/root_window.cc
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index 8ac31e76f47df6b693badcdfd21e7dbc53534c80..9f8da7d9b15e50c5d01d47cda03482db7621ae8b 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -64,8 +64,6 @@ void GetEventFiltersToNotify(Window* target, EventFilters* filters) {
       filters->push_back(target->event_filter());
     target = target->parent();
   }
-  if (Env::GetInstance()->event_filter())
-    filters->push_back(Env::GetInstance()->event_filter());
 }
 
 float GetDeviceScaleFactorFromDisplay(const Window* window) {
@@ -664,6 +662,18 @@ ui::TouchStatus RootWindow::ProcessTouchEvent(Window* target,
   if (!target->IsVisible())
     return ui::TOUCH_STATUS_UNKNOWN;
 
+  ui::Event::DispatcherApi dispatch_helper(event);
+  dispatch_helper.set_target(target);
+
+  const ui::EventHandlerList& pre_target =
+      Env::GetInstance()->pre_target_handlers();
+  for (ui::EventHandlerList::const_iterator iter = pre_target.begin();
+      iter != pre_target.end(); ++iter) {
+    ui::TouchStatus status = (*iter)->OnTouchEvent(event);
+    if (status != ui::TOUCH_STATUS_UNKNOWN)
+      return status;
+  }
+
   EventFilters filters;
   if (target == this)
     GetEventFiltersToNotify(target, &filters);
@@ -674,8 +684,6 @@ ui::TouchStatus RootWindow::ProcessTouchEvent(Window* target,
   WindowTracker tracker;
   tracker.Add(target);
 
-  ui::Event::DispatcherApi dispatcher(event);
-  dispatcher.set_target(target);
   for (EventFilters::const_reverse_iterator it = filters.rbegin(),
            rend = filters.rend();
        it != rend; ++it) {
@@ -791,8 +799,10 @@ bool RootWindow::CanDispatchToTarget(ui::EventTarget* target) {
 }
 
 void RootWindow::ProcessPreTargetList(ui::EventHandlerList* list) {
-  if (Env::GetInstance()->event_filter())
-    list->insert(list->begin(), Env::GetInstance()->event_filter());
+  const ui::EventHandlerList& pre_target =
+      Env::GetInstance()->pre_target_handlers();
+  if (pre_target.size() > 0)
+    list->insert(list->begin(), pre_target.begin(), pre_target.end());
 }
 
 void RootWindow::ProcessPostTargetList(ui::EventHandlerList* list) {