Move the concept of Activation to the Shell.

ui/aura_shell/activation_controller.h

+// 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.
+
+#ifndef UI_AURA_SHELL_ACTIVATION_CONTROLLER_H_
+#define UI_AURA_SHELL_ACTIVATION_CONTROLLER_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "ui/aura/client/activation_client.h"
+#include "ui/aura/root_window_observer.h"
+#include "ui/aura/window_observer.h"
+
+namespace aura_shell {
+namespace internal {
+
+class ActivationController : public aura::ActivationClient,
+                             public aura::WindowObserver,
+                             public aura::RootWindowObserver {
+ public:
+  ActivationController();
+  virtual ~ActivationController();
+
+  // Returns true if |window| exists within a container that supports
+  // activation.
+  static aura::Window* GetActivatableWindow(aura::Window* window);
+
+  // Returns true if |window| can be focused. To be focusable, |window| must
+  // exist inside an activatable window.
+  static bool CanFocusWindow(aura::Window* window);
+
+  // Overridden from aura::ActivationClient:
+  virtual void ActivateWindow(aura::Window* window) OVERRIDE;
+  virtual void DeactivateWindow(aura::Window* window) OVERRIDE;
+  virtual aura::Window* GetActiveWindow() OVERRIDE;
+
+  // Overridden from aura::WindowObserver:
+  virtual void OnWindowVisibilityChanged(aura::Window* window,
+                                         bool visible) OVERRIDE;
+  virtual void OnWindowDestroyed(aura::Window* window) OVERRIDE;
+
+  // Overridden from aura::RootWindowObserver:
+  virtual void OnWindowInitialized(aura::Window* window) OVERRIDE;
+  virtual void OnWindowFocused(aura::Window* window) OVERRIDE;
+
+#if defined(UNIT_TEST)
+  void set_default_container_for_test(aura::Window* window) {
+    default_container_for_test_ = window;
+  }
+#endif
+
+ private:
+  // Shifts activation to the next window, ignoring |window|.
+  void ActivateNextWindow(aura::Window* window);
+
+  // Returns the next window that should be activated, ignoring |ignore|.
+  aura::Window* GetTopmostWindowToActivate(aura::Window* ignore) const;
+
+  // True inside ActivateWindow(). Used to prevent recursion of focus
+  // change notifications causing activation.
+  bool updating_activation_;
+
+  // For tests that are not running with a Shell instance,
+  // ActivationController's attempts to locate the next active window in
+  // GetTopmostWindowToActivate() will crash, so we provide this way for such
+  // tests to specify a default container.
+  aura::Window* default_container_for_test_;
+
+  DISALLOW_COPY_AND_ASSIGN(ActivationController);
+};
+
+}  // namespace internal
+}  // namespace aura_shell
+
+#endif  // UI_AURA_SHELL_ACTIVATION_CONTROLLER_H_