Revert 114095 - Move the concept of Activation to the Shell.

ui/aura/client/activation_delegate.cc

-// Copyright (c) 2011 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/aura/client/activation_delegate.h"
-
-#include "ui/aura/client/aura_constants.h"
-#include "ui/aura/window.h"
-
-namespace aura {
-
-// static
-void ActivationDelegate::SetActivationDelegate(Window* window,
-                                               ActivationDelegate* delegate) {
-  window->SetProperty(kActivationDelegateKey, delegate);
-}
-
-// static
-ActivationDelegate* ActivationDelegate::GetActivationDelegate(Window* window) {
-  return reinterpret_cast<ActivationDelegate*>(
-      window->GetProperty(kActivationDelegateKey));
-}
-
-}  // namespace aura