Views a11y: Implement AXPlatformNode::FromNativeViewAccessible on all platforms.

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 df9880e44b331627cf5fb4aa470591fcef6c7c53..85891fd0b43dcbb14cf3025ffc536b61c3248c4e 100644
--- a/ui/views/accessibility/native_view_accessibility.h
+++ b/ui/views/accessibility/native_view_accessibility.h
@@ -40,13 +40,13 @@ 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 the instance for |view|, use GetForView() instead.
+  static std::unique_ptr<NativeViewAccessibility> CreateForView(View* view);
 
-  gfx::NativeViewAccessible GetNativeObject();
+  ~NativeViewAccessibility() override;
 
-  // Call Destroy rather than deleting this, because the subclass may
-  // use reference counting.
-  virtual void Destroy();
+  gfx::NativeViewAccessible GetNativeObject();
 
   void NotifyAccessibilityEvent(ui::AXEvent event_type);
 
@@ -74,7 +74,13 @@ class VIEWS_EXPORT NativeViewAccessibility
 
  protected:
   NativeViewAccessibility(View* view);
-  ~NativeViewAccessibility() override;
+
+  // Retrieves the NativeViewAccessibility instance for the given View. This
+  // invokes View::GetNativeViewAccessible() to ensure it exists.
+  static NativeViewAccessibility* GetForView(View* view);

[tapted, 2017/02/27 05:37:48]

Hm - this is the controversial bit that I was hoping to isolate in the other
CL... I don't think the change in views::View to make native_view_accessibility_
a std::unique_ptr relies on GetForView() (and that unique_ptr change is a good
change, that I don't think will be controversial at all).

[Patti Lor, 2017/03/03 02:55:54]

Done.

+
+  // Retrieves the gfx::NativeViewAccessibility for |view_|'s Widget/Rootview.
+  virtual gfx::NativeViewAccessible GetNativeViewAccessibleForWidget();
 
   // Weak. Owns this.
   View* view_;
@@ -85,6 +91,9 @@ 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