a11y: Move CreateTextMarker[Range] to TextMarkerHelperMac.

ui/accessibility/platform/text_marker_helper_mac.h

+// Copyright 2017 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 UI_ACCESSIBILITY_PLATFORM_TEXT_MARKER_HELPER_MAC_H_
+#define UI_ACCESSIBILITY_PLATFORM_TEXT_MARKER_HELPER_MAC_H_
+
+#import <Foundation/Foundation.h>
+
+#include <memory>
+
+#include "base/macros.h"
+#include "ui/accessibility/ax_enums.h"
+#include "ui/accessibility/ax_export.h"
+
+typedef struct OpaqueAXTextMarkerRef* AXTextMarkerRef;
+typedef struct OpaqueAXTextMarkerRangeRef* AXTextMarkerRangeRef;
+
+// TODO(tapted): Hide these.
+extern "C" {
+const UInt8* AXTextMarkerGetBytePtr(AXTextMarkerRef text_marker);
+size_t AXTextMarkerGetLength(AXTextMarkerRef text_marker);
+AXTextMarkerRef AXTextMarkerRangeCopyStartMarker(
+    AXTextMarkerRangeRef text_marker_range);
+AXTextMarkerRef AXTextMarkerRangeCopyEndMarker(
+    AXTextMarkerRangeRef text_marker_range);
+}
+
+namespace ui {
+
+class AXAbstractRange;
+class AXPositionBase;
+
+class AX_EXPORT PositionFactory {

[tapted, 2017/06/19 11:44:30]

(self review: comment)

+ public:
+  PositionFactory() {}
+  virtual ~PositionFactory() {}
+
+  virtual std::unique_ptr<AXPositionBase> GetRoot() const = 0;

[tapted, 2017/06/19 11:44:30]

(self review: these too)

+  virtual std::unique_ptr<AXAbstractRange> GetSelection() const = 0;
+  virtual std::unique_ptr<AXPositionBase> ExtractFromMarker(
+      AXTextMarkerRef marker) const = 0;
+};
+
+}  // namespace ui
+
+AX_EXPORT
+@interface TextMarkerHelperMac : NSObject

[tapted, 2017/06/19 11:44:30]

(self review: comment)

+
+- (instancetype)initWithFactory:(std::unique_ptr<ui::PositionFactory>)factory;
+
+// Returns a text marker that points to the first character in the document that
+// can be selected with VoiceOver.
+- (id)startTextMarker;
+
+// Returns a text marker that points to the last character in the document that
+// can be selected with VoiceOver.
+- (id)endTextMarker;
+
+// Returns a text marker range corresponding to the current selection.
+- (id)selectedTextMarkerRange;
+
+@end
+
+#endif  // UI_ACCESSIBILITY_PLATFORM_TEXT_MARKER_HELPER_MAC_H_