Migrate BrowserAccessibility windows unique id handling to AXPlatformNodeWin.

content/browser/accessibility/browser_accessibility_win.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 CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_WIN_H_
 #define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_WIN_H_
 
 #include <atlbase.h>
 #include <atlcom.h>
 
 #include "content/browser/accessibility/browser_accessibility.h"
 #include "content/browser/accessibility/browser_accessibility_com_win.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 class CONTENT_EXPORT BrowserAccessibilityWin : public BrowserAccessibility {
  public:
   BrowserAccessibilityWin();
   ~BrowserAccessibilityWin() override;
 
   // This is used to call UpdateStep1ComputeWinAttributes, ... above when
   // a node needs to be updated for some other reason other than via
   // OnAtomicUpdateFinished.
   void UpdatePlatformAttributes() override;
 
   //
   // BrowserAccessibility methods.
   //
+  int32_t unique_id() const override;
   void OnSubtreeWillBeDeleted() override;
   bool IsNative() const override;
   void OnLocationChanged() override;
   base::string16 GetText() const override;
 
   gfx::NativeViewAccessible GetNativeViewAccessible() override;
   ui::AXPlatformNode* GetFromNodeID(int32_t id) override;
 
   class BrowserAccessibilityComWin* GetCOM() const;
 
  private:
   CComObject<BrowserAccessibilityComWin>* browser_accessibility_com_;
   // Give BrowserAccessibility::Create access to our constructor.
   friend class BrowserAccessibility;
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityWin);
 };
 
 CONTENT_EXPORT BrowserAccessibilityWin*
 ToBrowserAccessibilityWin(BrowserAccessibility* obj);
 
 CONTENT_EXPORT const BrowserAccessibilityWin*
 ToBrowserAccessibilityWin(const BrowserAccessibility* obj);
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_WIN_H_