a11y: Exclude children of nested keyboard accessible controls from a11y tree.

ui/views/accessibility/native_view_accessibility.h

Index: ui/views/accessibility/native_view_accessibility.h
diff --git a/ui/views/accessibility/native_view_accessibility.h b/ui/views/accessibility/native_view_accessibility.h
index f4d61b3f87919fc25799dea2ae7c171ad2c9af63..c419a6dc66c8fd52a7c7b8556c6ad7e8bc246ba7 100644
--- a/ui/views/accessibility/native_view_accessibility.h
+++ b/ui/views/accessibility/native_view_accessibility.h
@@ -5,6 +5,8 @@
 #ifndef UI_VIEWS_ACCESSIBILITY_NATIVE_VIEW_ACCESSIBILITY_H_
 #define UI_VIEWS_ACCESSIBILITY_NATIVE_VIEW_ACCESSIBILITY_H_
 
+#include <map>
+
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "ui/accessibility/ax_action_data.h"
@@ -36,13 +38,17 @@ class VIEWS_EXPORT NativeViewAccessibility
     : public ui::AXPlatformNodeDelegate,
       public WidgetObserver {
  public:
-  static NativeViewAccessibility* Create(View* view);
+  // A method for View to create a new NativeViewAccessibility instance for the
+  // given View. To retrieve an instance for |view|, use GetForView() instead.
+  static std::unique_ptr<NativeViewAccessibility> CreateForView(View* view);
 
-  gfx::NativeViewAccessible GetNativeObject();
+  // Retrieves the NativeViewAccessibility instance for the given View. This
+  // calls CreateForView() if it doesn't yet exist.
+  static NativeViewAccessibility* GetForView(View* view);
 
-  // Call Destroy rather than deleting this, because the subclass may
-  // use reference counting.
-  virtual void Destroy();
+  ~NativeViewAccessibility() override;
+
+  gfx::NativeViewAccessible GetNativeObject();
 
   void NotifyAccessibilityEvent(ui::AXEvent event_type);
 
@@ -70,7 +76,6 @@ class VIEWS_EXPORT NativeViewAccessibility
 
  protected:
   NativeViewAccessibility(View* view);
-  ~NativeViewAccessibility() override;
 
   // Weak. Owns this.
   View* view_;
@@ -81,6 +86,9 @@ class VIEWS_EXPORT NativeViewAccessibility
   Widget* parent_widget_;
 
  private:
+  // Creates new platform-specific NativeViewAccessibility subclass instances.
+  static NativeViewAccessibility* Create(View* view);
+
   void PopulateChildWidgetVector(std::vector<Widget*>* result_child_widgets);
 
   // We own this, but it is reference-counted on some platforms so we can't use