exo: Fix dragging edge cases

components/exo/wm_helper.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_EXO_WM_HELPER_H_
 #define COMPONENTS_EXO_WM_HELPER_H_
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "ui/base/cursor/cursor.h"
@@ skipping 35 matching lines @@
 
   class CursorObserver {
    public:
     virtual void OnCursorVisibilityChanged(bool is_visible) {}
     virtual void OnCursorSetChanged(ui::CursorSetType cursor_set) {}
 
    protected:
     virtual ~CursorObserver() {}
   };
 
-  class MaximizeModeObserver {
+  class ShellObserver {
    public:
-    virtual void OnMaximizeModeStarted() = 0;
-    virtual void OnMaximizeModeEnded() = 0;
+    virtual void OnMaximizeModeStarted() {}
+    virtual void OnMaximizeModeEnded() {}
+
+    virtual void OnOverviewModeStarted() {}
+    virtual void OnOverviewModeEnded() {}
 
    protected:
-    virtual ~MaximizeModeObserver() {}
+    virtual ~ShellObserver() {}
   };
 
   virtual ~WMHelper();
 
   static void SetInstance(WMHelper* helper);
   static WMHelper* GetInstance();
 
   void AddActivationObserver(ActivationObserver* observer);
   void RemoveActivationObserver(ActivationObserver* observer);
   void AddFocusObserver(FocusObserver* observer);
   void RemoveFocusObserver(FocusObserver* observer);
   void AddCursorObserver(CursorObserver* observer);
   void RemoveCursorObserver(CursorObserver* observer);
-  void AddMaximizeModeObserver(MaximizeModeObserver* observer);
-  void RemoveMaximizeModeObserver(MaximizeModeObserver* observer);
+  void AddShellObserver(ShellObserver* observer);
+  void RemoveShellObserver(ShellObserver* observer);
 
   virtual const display::ManagedDisplayInfo GetDisplayInfo(
       int64_t display_id) const = 0;
   virtual aura::Window* GetContainer(int container_id) = 0;
   virtual aura::Window* GetActiveWindow() const = 0;
   virtual aura::Window* GetFocusedWindow() const = 0;
   virtual ui::CursorSetType GetCursorSet() const = 0;
   virtual void AddPreTargetHandler(ui::EventHandler* handler) = 0;
   virtual void PrependPreTargetHandler(ui::EventHandler* handler) = 0;
   virtual void RemovePreTargetHandler(ui::EventHandler* handler) = 0;
   virtual void AddPostTargetHandler(ui::EventHandler* handler) = 0;
   virtual void RemovePostTargetHandler(ui::EventHandler* handler) = 0;
   virtual bool IsMaximizeModeWindowManagerEnabled() const = 0;
 
  protected:
   WMHelper();
 
   void NotifyWindowActivated(aura::Window* gained_active,
                              aura::Window* lost_active);
   void NotifyWindowFocused(aura::Window* gained_focus,
                            aura::Window* lost_focus);
   void NotifyCursorVisibilityChanged(bool is_visible);
   void NotifyCursorSetChanged(ui::CursorSetType cursor_set);
   void NotifyMaximizeModeStarted();
   void NotifyMaximizeModeEnded();
+  void NotifyOverviewModeStarted();
+  void NotifyOverviewModeEnded();
 
  private:
   base::ObserverList<ActivationObserver> activation_observers_;
   base::ObserverList<FocusObserver> focus_observers_;
   base::ObserverList<CursorObserver> cursor_observers_;
-  base::ObserverList<MaximizeModeObserver> maximize_mode_observers_;
+  base::ObserverList<ShellObserver> shell_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(WMHelper);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_WM_HELPER_H_