Use BrowserAccessibilityComWin::Destroy to clear delegate and owner.

content/browser/accessibility/browser_accessibility_com_win.h

Index: content/browser/accessibility/browser_accessibility_com_win.h
diff --git a/content/browser/accessibility/browser_accessibility_com_win.h b/content/browser/accessibility/browser_accessibility_com_win.h
index 5bfac2e0b0b670ed515ae199258c6bc96788dfb6..babed944bdccfaa89e6654ca34d3514307e40d0d 100644
--- a/content/browser/accessibility/browser_accessibility_com_win.h
+++ b/content/browser/accessibility/browser_accessibility_com_win.h
@@ -747,6 +747,11 @@ class __declspec(uuid("562072fe-3390-43b1-9e2c-dd4118f5ac79"))
 
   BrowserAccessibilityManager* Manager() const;
 
+  //
+  // AXPlatformNode overrides
+  //
+  void Destroy() override;
+
   // Returns the IA2 text attributes for this object.
   std::vector<base::string16> ComputeTextAttributes() const;