RenderTextWin: Break runs between any two characters that are not in the same code block

base/i18n/char_iterator.h

Index: base/i18n/char_iterator.h
diff --git a/base/i18n/char_iterator.h b/base/i18n/char_iterator.h
index 46928b37d0bf5ba705b1fd1d411fe08046cacb24..33eebff42f3a54a9e225d781b02198b497b6dc9d 100644
--- a/base/i18n/char_iterator.h
+++ b/base/i18n/char_iterator.h
@@ -33,15 +33,15 @@ class BASE_I18N_EXPORT UTF8CharIterator {
   explicit UTF8CharIterator(const std::string* str);
   ~UTF8CharIterator();
 
-  // Return the starting array index of the current character within the
+  // Returns the starting array index of the current character within the
   // string.
   int32 array_pos() const { return array_pos_; }
 
-  // Return the logical index of the current character, independent of the
+  // Returns the logical index of the current character, independent of the
   // number of bytes each character takes.
   int32 char_pos() const { return char_pos_; }
 
-  // Return the current char.
+  // Returns the current char.
   int32 get() const { return char_; }
 
   // Returns true if we're at the end of the string.
@@ -51,6 +51,11 @@ class BASE_I18N_EXPORT UTF8CharIterator {
   // end of the string.
   bool Advance();
 
+  // Set the iterator to the specified |position|. If |position| is not a code
+  // point boundary, the position is set to the beginning of the code point.
+  // Calling this function invalidates all future |char_pos()| results.
+  void SetPosition(int32 position);
+
  private:
   // The string we're iterating over.
   const uint8_t* str_;
@@ -80,15 +85,15 @@ class BASE_I18N_EXPORT UTF16CharIterator {
   UTF16CharIterator(const char16* str, size_t str_len);
   ~UTF16CharIterator();
 
-  // Return the starting array index of the current character within the
+  // Returns the starting array index of the current character within the
   // string.
   int32 array_pos() const { return array_pos_; }
 
-  // Return the logical index of the current character, independent of the
+  // Returns the logical index of the current character, independent of the
   // number of codewords each character takes.
   int32 char_pos() const { return char_pos_; }
 
-  // Return the current char.
+  // Returns the current char.
   int32 get() const { return char_; }
 
   // Returns true if we're at the end of the string.
@@ -98,6 +103,11 @@ class BASE_I18N_EXPORT UTF16CharIterator {
   // end of the string.
   bool Advance();
 
+  // Set the iterator to the specified |position|. If |position| is not a code
+  // point boundary, the position is set to the beginning of the code point.
+  // Calling this function invalidates all future |char_pos()| results.
+  void SetPosition(int32 position);
+
  private:
   // Fills in the current character we found and advances to the next
   // character, updating all flags as necessary.