cros: allow aura window not considered activatable for pointer event

ui/wm/core/focus_rules.h

 // Copyright (c) 2012 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_WM_CORE_FOCUS_RULES_H_
 #define UI_WM_CORE_FOCUS_RULES_H_
 
 #include "ui/wm/wm_export.h"
 
 namespace aura {
 class Window;
 }
 
+namespace ui {
+class Event;
+}
+
 namespace wm {
 
 // Implemented by an object that establishes the rules about what can be
 // focused or activated.
 class WM_EXPORT FocusRules {
  public:
   virtual ~FocusRules() {}
 
   // Returns true if |window| is a toplevel window. Whether or not a window
   // is considered toplevel is determined by a similar set of rules that
   // govern activation and focus. Not all toplevel windows are activatable,
   // call CanActivateWindow() to determine if a window can be activated.
   virtual bool IsToplevelWindow(aura::Window* window) const = 0;
   // Returns true if |window| can be activated or focused.
   virtual bool CanActivateWindow(aura::Window* window) const = 0;
-  // For CanFocusWindow(), NULL is supported, because NULL is a valid focusable
-  // window (in the case of clearing focus).
-  virtual bool CanFocusWindow(aura::Window* window) const = 0;
+  // For CanFocusWindow(), nullptr window is supported, because nullptr is a

[sky, 2017/04/17 16:08:48]

optional: in comments I think null is fine.

[Qiang(Joe) Xu, 2017/04/17 17:40:32]

Done.

+  // valid focusable window (in the case of clearing focus).
+  // |event| can be provided to check whether for the |event| the default focus

[sky, 2017/04/17 16:08:48]

How about:
If |event| is non-null it is the event triggering the focus change.

[Qiang(Joe) Xu, 2017/04/17 17:40:32]

Done.

+  // rules for |window| should be disabled.
+  virtual bool CanFocusWindow(aura::Window* window, ui::Event* event) const = 0;
 
   // Returns the toplevel window containing |window|. Not all toplevel windows
   // are activatable, call GetActivatableWindow() instead to return the
   // activatable window, which might be in a different hierarchy.
   // Will return NULL if |window| is not contained by a window considered to be
   // a toplevel window.
   virtual aura::Window* GetToplevelWindow(aura::Window* window) const = 0;
   // Returns the activatable or focusable window given an attempt to activate or
   // focus |window|. Some possible scenarios (not intended to be exhaustive):
   // - |window| is a child of a non-focusable window and so focus must be set
@@ skipping 15 matching lines @@
   // - it is being destroyed.
   // - it is being explicitly deactivated.
   // |ignore| cannot be NULL.
   virtual aura::Window* GetNextActivatableWindow(
       aura::Window* ignore) const = 0;
 };
 
 }  // namespace wm
 
 #endif  // UI_WM_CORE_FOCUS_RULES_H_