Reland of Improves focus/activation for aura-mus and DesktopNativeWidgetAura

ui/views/mus/desktop_window_tree_host_mus.h

 // Copyright 2016 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_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_MUS_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_MUS_H_
 
 #include <memory>
 #include <set>
 
 #include "base/macros.h"
+#include "ui/aura/env_observer.h"
 #include "ui/aura/mus/window_tree_host_mus.h"
 #include "ui/views/mus/mus_export.h"
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host.h"
 
 namespace views {
 
 class VIEWS_MUS_EXPORT DesktopWindowTreeHostMus
     : public DesktopWindowTreeHost,
-      public aura::WindowTreeHostMus {
+      public aura::WindowTreeHostMus,
+      public aura::EnvObserver {
  public:
   DesktopWindowTreeHostMus(
       internal::NativeWidgetDelegate* native_widget_delegate,
       DesktopNativeWidgetAura* desktop_native_widget_aura);
   ~DesktopWindowTreeHostMus() override;
 
  private:
   bool IsDocked() const;
 
   // DesktopWindowTreeHost:
@@ skipping 50 matching lines @@
   void SetOpacity(float opacity) override;
   void SetWindowIcons(const gfx::ImageSkia& window_icon,
                       const gfx::ImageSkia& app_icon) override;
   void InitModalType(ui::ModalType modal_type) override;
   void FlashFrame(bool flash_frame) override;
   void OnRootViewLayout() override;
   bool IsAnimatingClosed() const override;
   bool IsTranslucentWindowOpacitySupported() const override;
   void SizeConstraintsChanged() override;
 
+  // aura::EnvObserver:
+  void OnWindowInitialized(aura::Window* window) override;
+  void OnActiveFocusClientChanged(aura::client::FocusClient* focus_client,
+                                  aura::Window* window) override;
+
   internal::NativeWidgetDelegate* native_widget_delegate_;
 
   DesktopNativeWidgetAura* desktop_native_widget_aura_;
 
   // State to restore window to when exiting fullscreen. Only valid if
   // fullscreen.
   ui::WindowShowState fullscreen_restore_state_;
 
   // We can optionally have a parent which can order us to close, or own
   // children who we're responsible for closing when we CloseNow().
   DesktopWindowTreeHostMus* parent_ = nullptr;
   std::set<DesktopWindowTreeHostMus*> children_;
 
+  bool is_active_ = false;
+
   // Used so that Close() isn't immediate.
   base::WeakPtrFactory<DesktopWindowTreeHostMus> close_widget_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopWindowTreeHostMus);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_MUS_H_