Hook up the FocusController behind a flag.

ui/views/corewm/focus_change_shim.h

Index: ui/views/corewm/focus_change_shim.h
===================================================================
--- ui/views/corewm/focus_change_shim.h	(revision 0)
+++ ui/views/corewm/focus_change_shim.h	(revision 0)
@@ -0,0 +1,47 @@
+// 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.
+
+#ifndef UI_VIEWS_COREWM_FOCUS_CHANGE_SHIM_
+#define UI_VIEWS_COREWM_FOCUS_CHANGE_SHIM_
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "ui/aura/client/focus_change_observer.h"
+#include "ui/base/events/event_handler.h"
+#include "ui/views/corewm/focus_change_event.h"
+#include "ui/views/views_export.h"
+
+namespace ui {
+class EventTarget;
+}
+
+namespace views {
+namespace corewm {
+
+// A class that converts FocusChangeEvents to calls to an
+// FocusChangeObserver. An interim bandaid that allows us to incrementally
+// convert observers to use the new FocusController.
+class VIEWS_EXPORT FocusChangeShim
+    : public aura::client::FocusChangeObserver,
+      public ui::EventHandler {
+ protected:
+  explicit FocusChangeShim(ui::EventTarget* target);
+  virtual ~FocusChangeShim();
+
+  // Overridden from aura::client::FocusChangeObserver:
+  virtual void OnWindowFocused(aura::Window* window) OVERRIDE;
+
+  // Overridden from ui::EventHandler:
+  virtual ui::EventResult OnEvent(ui::Event* event) OVERRIDE;
+
+ private:
+  ui::EventTarget* target_;
+
+  DISALLOW_COPY_AND_ASSIGN(FocusChangeShim);
+};
+
+}  // namespace corewm
+}  // namespace views
+
+#endif  // UI_VIEWS_COREWM_FOCUS_CHANGE_SHIM_