Creates AXPosition to uniquely identify a position in the accessibility tree

content/browser/accessibility/ax_platform_position.h

+// Copyright 2016 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_AX_PLATFORM_POSITION_H_
+#define CONTENT_BROWSER_ACCESSIBILITY_AX_PLATFORM_POSITION_H_
+
+#include <stdint.h>
+
+#include <memory>
+
+#include "content/browser/accessibility/ax_tree_id_registry.h"
+#include "content/browser/accessibility/browser_accessibility.h"
+#include "content/browser/accessibility/browser_accessibility_manager.h"
+#include "ui/accessibility/ax_node.h"
+#include "ui/accessibility/ax_position.h"
+
+namespace content {
+
+class AXPlatformPositionFactory;
+
+class AXPlatformPosition : ui::AXPosition {
+ public:
+  ~AXPlatformPosition() override;
+
+ protected:
+  friend class AXPlatformPositionFactory;
+  AXPlatformPosition(AXTreeIDRegistry::AXTreeID tree_id,
+                     int32_t anchor_id,
+                     int child_index,
+                     int text_offset,
+                     ui::AXPositionType type,
+                     std::unique_ptr<ui::AXPositionFactory> factory =

[dmazzoni, 2016/10/04 20:08:24]

It's not necessarily a bad idea to have an object have
a reference to some object that owns it or manages it,
but as currently designed every AXPosition has to have
its own unique factory. I don't see why we need so many
factories. At a minimum couldn't this be a shared_ptr?

+                         std::make_unique<AXPlatformPositionFactory>());
+
+  BrowserAccessibility* GetPlatformNodeInTree(
+      AXTreeIDRegistry::AXTreeID tree_id,
+      int32_t node_id) const;
+  ui::AXNode* GetNodeInTree(AXTreeIDRegistry::AXTreeID tree_id,
+                            int32_t node_id) const override;
+  int MaxTextOffset() const override;
+};
+
+class AXPlatformPositionFactory : ui::AXPositionFactory {
+ public:
+  virtual ~AXPlatformPositionFactory() {}
+
+  ui::AXPosition CreateNullPosition() override;
+  ui::AXPosition CreateTreePosition(int tree_id,
+                                    int32_t anchor_id,
+                                    int child_index) override;
+  ui::AXPosition CreateTextPosition(int tree_id,
+                                    int32_t anchor_id,
+                                    int text_offset) override;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_ACCESSIBILITY_AX_PLATFORM_POSITION_H_