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

ui/accessibility/platform/ax_platform_node_win.cc

 // 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.
 
 #include <atlbase.h>
 #include <atlcom.h>
 #include <limits.h>
 #include <oleacc.h>
 #include <stdint.h>
 
@@ skipping 120 matching lines @@
 }
 
 //
 // AXPlatformNodeWin
 //
 
 AXPlatformNodeWin::AXPlatformNodeWin() {
 }
 
 AXPlatformNodeWin::~AXPlatformNodeWin() {
-  CHECK(!delegate_);
+}
+
+//
+// AXPlatformNodeBase implementation.
+//
+
+void AXPlatformNodeWin::Dispose() {
+  Release();
+}
+
+void AXPlatformNodeWin::Destroy() {
+  RemoveAlertTarget();
+  AXPlatformNodeBase::Destroy();
 }
 
 //
 // AXPlatformNode implementation.
 //
 
-void AXPlatformNodeWin::Destroy() {
-  AXPlatformNode::Destroy();
-  // Do not call base class AXPlatformNodeBase::Destroy method because it
-  // would delete this object. Call base's base class AXPlatformNode::Destroy
-  // instead to remove the unique ID from the map like base class does.
-  delegate_ = nullptr;
-  RemoveAlertTarget();
-  Release();
-}
-
 gfx::NativeViewAccessible AXPlatformNodeWin::GetNativeViewAccessible() {
   return this;
 }
 
 void AXPlatformNodeWin::NotifyAccessibilityEvent(ui::AXEvent event_type) {
   HWND hwnd = delegate_->GetTargetForNativeAccessibilityEvent();
   if (!hwnd)
     return;
 
   // Menu items fire selection events but Windows screen readers work reliably
@@ skipping 972 matching lines @@
     LONG start_offset,
     ui::TextBoundaryDirection direction) {
   HandleSpecialTextOffset(text, &start_offset);
   ui::TextBoundaryType boundary = IA2TextBoundaryToTextBoundary(ia2_boundary);
   std::vector<int32_t> line_breaks;
   return static_cast<LONG>(ui::FindAccessibleTextBoundary(
       text, line_breaks, boundary, start_offset, direction));
 }
 
 }  // namespace ui