Manage DOM and string offsets separately in TextIteratorTextState

third_party/WebKit/Source/core/editing/iterators/TextIteratorTextState.h

Index: third_party/WebKit/Source/core/editing/iterators/TextIteratorTextState.h
diff --git a/third_party/WebKit/Source/core/editing/iterators/TextIteratorTextState.h b/third_party/WebKit/Source/core/editing/iterators/TextIteratorTextState.h
index f81bb8fed902e50b89d21c3fbbd61b9589dc192d..64dbf2f519a1c2bd2c7102129d8b3c0fcf3d49b7 100644
--- a/third_party/WebKit/Source/core/editing/iterators/TextIteratorTextState.h
+++ b/third_party/WebKit/Source/core/editing/iterators/TextIteratorTextState.h
@@ -44,12 +44,16 @@ class CORE_EXPORT TextIteratorTextState
   explicit TextIteratorTextState(const TextIteratorBehavior&);
   ~TextIteratorTextState() {}
 
+  // Return properties of the current text.
   int length() const { return text_length_; }
   UChar CharacterAt(unsigned index) const;
   String Substring(unsigned position, unsigned length) const;
   void AppendTextToStringBuilder(StringBuilder&,
                                  unsigned position = 0,
                                  unsigned max_length = UINT_MAX) const;
+  void AppendTextTo(ForwardsTextBuffer* output,
+                    unsigned position,
+                    unsigned length_to_append) const;
 
   void SpliceBuffer(UChar,
                     Node* text_node,
@@ -62,35 +66,36 @@ class CORE_EXPORT TextIteratorTextState
                 int text_end_offset);
   void EmitAltText(Node*);
   void UpdateForReplacedElement(Node* base_node);
+
+  // Return position of the current text.
   void FlushPositionOffsets() const;
   int PositionStartOffset() const { return position_start_offset_; }
   int PositionEndOffset() const { return position_end_offset_; }
   Node* PositionNode() const { return position_node_; }
+
   bool HasEmitted() const { return has_emitted_; }
   UChar LastCharacter() const { return last_character_; }
-  int TextStartOffset() const { return text_start_offset_; }
   void ResetRunInformation() {
     position_node_ = nullptr;
     text_length_ = 0;
   }
 
-  void AppendTextTo(ForwardsTextBuffer* output,
-                    unsigned position,
-                    unsigned length_to_append) const;
-
   DECLARE_TRACE();
 
  private:
   int text_length_ = 0;
-  String text_;
 
   // Used for whitespace characters that aren't in the DOM, so we can point at
   // them.
-  // If non-zero, overrides m_text.
+  // If non-zero, overrides |text_|.
   UChar single_character_buffer_ = 0;
 
-  // The current text and its position, in the form to be returned from the
-  // iterator.
+  // The current text when |single_character_buffer_| is zero, in which case it
+  // is |text_.Substring(text_start_offset_, text_length_)|.
+  String text_;
+  int text_start_offset_ = 0;
+
+  // Position of the current text, in the form to be returned from the iterator.
   Member<Node> position_node_;
   mutable Member<Node> position_offset_base_node_;
   mutable int position_start_offset_ = 0;
@@ -103,10 +108,6 @@ class CORE_EXPORT TextIteratorTextState
 
   const TextIteratorBehavior behavior_;
 
-  // Stores the length of :first-letter when we are at the remaining text.
-  // Equals to 0 in all other cases.
-  int text_start_offset_ = 0;
-
   DISALLOW_COPY_AND_ASSIGN(TextIteratorTextState);
 };