ARC IME: Fix Crash on ARC Notification

components/arc/ime/arc_ime_service.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 COMPONENTS_ARC_IME_ARC_IME_SERVICE_H_
 #define COMPONENTS_ARC_IME_ARC_IME_SERVICE_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "components/arc/arc_service.h"
 #include "components/arc/ime/arc_ime_bridge.h"
 #include "components/exo/wm_helper.h"
 #include "ui/aura/env_observer.h"
 #include "ui/aura/window_observer.h"
-#include "ui/aura/window_tracker.h"
 #include "ui/base/ime/text_input_client.h"
 #include "ui/base/ime/text_input_flags.h"
 #include "ui/base/ime/text_input_type.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/keyboard/keyboard_controller.h"
 #include "ui/keyboard/keyboard_controller_observer.h"
 
 namespace aura {
 class Window;
 }
 
 namespace ui {
 class InputMethod;
 }
 
 namespace arc {
 
 class ArcBridgeService;
 
 // This class implements ui::TextInputClient and makes ARC windows behave
 // as a text input target in Chrome OS environment.
 class ArcImeService : public ArcService,
                       public ArcImeBridge::Delegate,
                       public aura::EnvObserver,
+                      public aura::WindowObserver,
                       public exo::WMHelper::FocusObserver,
                       public keyboard::KeyboardControllerObserver,
                       public ui::TextInputClient {
  public:
   explicit ArcImeService(ArcBridgeService* bridge_service);
   ~ArcImeService() override;
 
   class ArcWindowDelegate {
    public:
     virtual ~ArcWindowDelegate() {}
     virtual bool IsArcWindow(const aura::Window* window) const = 0;
     virtual void RegisterFocusObserver() = 0;
     virtual void UnregisterFocusObserver() = 0;
   };
 
   // Injects the custom IPC bridge object for testing purpose only.
   void SetImeBridgeForTesting(std::unique_ptr<ArcImeBridge> test_ime_bridge);
 
   // Injects the custom IME for testing purpose only.
   void SetInputMethodForTesting(ui::InputMethod* test_input_method);
 
   // Injects the custom delegate for ARC windows, for testing purpose only.
   void SetArcWindowDelegateForTesting(
       std::unique_ptr<ArcWindowDelegate> delegate);
 
   // Overridden from aura::EnvObserver:
   void OnWindowInitialized(aura::Window* new_window) override;
 
+  // Overridden from aura::WindowObserver:
+  void OnWindowDestroying(aura::Window* window) override;
+  void OnWindowRemovingFromRootWindow(aura::Window* window,
+                                      aura::Window* new_root) override;
+
   // Overridden from exo::WMHelper::FocusObserver:
   void OnWindowFocused(aura::Window* gained_focus,
                        aura::Window* lost_focus) override;
 
   // Overridden from ArcImeBridge::Delegate:
   void OnTextInputTypeChanged(ui::TextInputType type) override;
   void OnCursorRectChanged(const gfx::Rect& rect) override;
   void OnCancelComposition() override;
   void ShowImeIfNeeded() override;
 
@@ skipping 38 matching lines @@
 
  private:
   ui::InputMethod* GetInputMethod();
 
   std::unique_ptr<ArcImeBridge> ime_bridge_;
   std::unique_ptr<ArcWindowDelegate> arc_window_delegate_;
   ui::TextInputType ime_type_;
   gfx::Rect cursor_rect_;
   bool has_composition_text_;
 
-  aura::WindowTracker focused_arc_window_;
+  aura::Window* focused_arc_window_ = nullptr;
 
   keyboard::KeyboardController* keyboard_controller_;
 
   ui::InputMethod* test_input_method_;
   bool is_focus_observer_installed_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcImeService);
 };
 
 }  // namespace arc
 
 #endif  // COMPONENTS_ARC_IME_ARC_IME_SERVICE_H_