aura: A couple of API cleanups.

ui/views/widget/desktop_aura/desktop_native_widget_aura.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/views/widget/desktop_aura/desktop_native_widget_aura.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/cursor_client.h"
@@ skipping 419 matching lines @@
         new wm::WindowModalityController(host_->window()));
 
   // |root_window_event_filter_| must be created before
   // OnWindowTreeHostCreated() is invoked.
 
   // CEF sets focus to the window the user clicks down on.
   // TODO(beng): see if we can't do this some other way. CEF seems a heavy-
   //             handed way of accomplishing focus.
   // No event filter for aura::Env. Create CompoundEvnetFilter per
   // WindowEventDispatcher.
-  root_window_event_filter_ = new wm::CompoundEventFilter;
-  // Pass ownership of the filter to the root_window.
-  host_->window()->SetEventFilter(root_window_event_filter_);
+  root_window_event_filter_.reset(new wm::CompoundEventFilter);
+  host_->window()->AddPreTargetHandler(root_window_event_filter_.get());
 
   // The host's dispatcher must be added to |native_cursor_manager_| before
   // OnNativeWidgetCreated() is called.
   cursor_reference_count_++;
   if (!native_cursor_manager_) {
     native_cursor_manager_ = new DesktopNativeCursorManager(
         DesktopCursorLoaderUpdater::Create());
   }
   if (!cursor_manager_) {
     cursor_manager_ = new wm::CursorManager(
@@ skipping 734 matching lines @@
   if (cursor_reference_count_ == 0) {
     // We are the last DesktopNativeWidgetAura instance, and we are responsible
     // for cleaning up |cursor_manager_|.
     delete cursor_manager_;
     native_cursor_manager_ = NULL;
     cursor_manager_ = NULL;
   }
 }
 
 }  // namespace views