Introduce range-based for loop in LayoutSelection.

third_party/WebKit/Source/core/editing/LayoutSelection.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 26 matching lines @@
 // 2 LayoutObjects are only valid for |Text| node without 'transform' or
 // 'first-letter'.
 // TODO(editing-dev): Clarify the meaning of "offset".
 // editing/ passes them as offsets in the DOM tree but layout uses them as
 // offset in the layout tree. This doesn't work in the cases of
 // CSS first-letter or character transform. See crbug.com/17528.
 class SelectionPaintRange {
   DISALLOW_NEW();
 
  public:
+  class Iterator
+      : public std::iterator<std::input_iterator_tag, LayoutObject*> {
+   public:
+    explicit Iterator(const SelectionPaintRange*);
+    Iterator(const Iterator&) = default;
+    bool operator==(const Iterator& other) const {
+      return current_ == other.current_;
+    }
+    bool operator!=(const Iterator& other) const {
+      return current_ != other.current_;

[yosin_UTC9, 2017/06/02 08:35:44]

|return !operator==(other)| is better.

[yoichio, 2017/06/12 06:12:52]

Done.

+    }
+    Iterator& operator++();
+    LayoutObject* operator*() const { return current_; }

[yosin_UTC9, 2017/06/02 08:35:44]

We should have DCHECK(current_);

[yoichio, 2017/06/12 06:12:52]

Done.

+
+   private:
+    LayoutObject* current_;
+    const LayoutObject* included_end_;
+    const LayoutObject* stop_;
+  };
+  Iterator begin() const { return Iterator(this); };
+  Iterator end() const { return Iterator(nullptr); };
+
   SelectionPaintRange() = default;
   SelectionPaintRange(LayoutObject* start_layout_object,
                       int start_offset,
                       LayoutObject* end_layout_object,
                       int end_offset);
 
   bool operator==(const SelectionPaintRange& other) const;
 
   LayoutObject* StartLayoutObject() const;
   int StartOffset() const;
@@ skipping 36 matching lines @@
 
   Member<FrameSelection> frame_selection_;
   bool has_pending_selection_ : 1;
 
   SelectionPaintRange paint_range_;
 };
 
 }  // namespace blink
 
 #endif