Revert of Avoid two targeting phases in aura client-lib and EventProcessor.

ash/root_window_controller.cc

Index: ash/root_window_controller.cc
diff --git a/ash/root_window_controller.cc b/ash/root_window_controller.cc
index f621e8057ae19b9a32e3ed749acc0549d112234c..dde74bfe0942b6acf274acfe1c779490e324b9ae 100644
--- a/ash/root_window_controller.cc
+++ b/ash/root_window_controller.cc
@@ -486,9 +486,8 @@
                             location_in_root, ui::EventTimeForNow(),
                             ui::EF_NONE, ui::EF_NONE);
   ui::EventTarget* event_handler =
-      root_window->GetHost()
-          ->dispatcher()
-          ->GetDefaultEventTargeter()
+      static_cast<ui::EventTarget*>(root_window)
+          ->GetEventTargeter()
           ->FindTargetForEvent(root_window, &test_event);
   return WmWindow::Get(static_cast<aura::Window*>(event_handler));
 }