Clean up code and logic related to platform accessibility node destruction.

ui/accessibility/platform/ax_platform_node_win.h

 // Copyright 2015 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_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_WIN_H_
 #define UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_WIN_H_
 
 #include <atlbase.h>
 #include <atlcom.h>
 #include <oleacc.h>
@@ skipping 36 matching lines @@
     COM_INTERFACE_ENTRY(IAccessible)
     COM_INTERFACE_ENTRY(IAccessible2)
     COM_INTERFACE_ENTRY(IAccessible2_2)
     COM_INTERFACE_ENTRY(IAccessibleText)
     COM_INTERFACE_ENTRY(IServiceProvider)
   END_COM_MAP()
 
   ~AXPlatformNodeWin() override;
 
   // AXPlatformNode overrides.
-  void Destroy() override;
   gfx::NativeViewAccessible GetNativeViewAccessible() override;
   void NotifyAccessibilityEvent(ui::AXEvent event_type) override;
 
   // AXPlatformNodeBase overrides.
+  void Destroy() override;
   int GetIndexInParent() override;
 
   //
   // IAccessible methods.
   //
 
   // Retrieves the child element or child object at a given point on the screen.
   STDMETHODIMP accHitTest(LONG x_left, LONG y_top, VARIANT* child) override;
 
   // Performs the object's default action.
@@ skipping 188 matching lines @@
   // IServiceProvider methods.
   //
 
   STDMETHODIMP QueryService(REFGUID guidService,
                             REFIID riid,
                             void** object) override;
 
  protected:
   AXPlatformNodeWin();
 
+  // AXPlatformNodeBase overrides.
+  void Dispose() override;
+
  private:
   bool IsValidId(const VARIANT& child) const;
   int MSAARole();
   int MSAAState();
   int MSAAEvent(ui::AXEvent event);
 
   HRESULT GetStringAttributeAsBstr(
       ui::AXStringAttribute attribute,
       BSTR* value_bstr) const;
 
@@ skipping 15 matching lines @@
   // return the offset of that boundary.
   LONG FindBoundary(const base::string16& text,
                     IA2TextBoundaryType ia2_boundary,
                     LONG start_offset,
                     ui::TextBoundaryDirection direction);
 };
 
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_WIN_H_