adding baseline options for super/sub scripting

ui/gfx/render_text.h

Index: ui/gfx/render_text.h
diff --git a/ui/gfx/render_text.h b/ui/gfx/render_text.h
index 5a1825351bdf5c8bc97b7b754e1d3be3f7c2b7ea..edbfe166cee96840198b5ee3c5ed90ae6e7d9b09 100644
--- a/ui/gfx/render_text.h
+++ b/ui/gfx/render_text.h
@@ -109,15 +109,18 @@ class SkiaTextRenderer {
   DISALLOW_COPY_AND_ASSIGN(SkiaTextRenderer);
 };
 
-// Internal helper class used by derived classes to iterate colors and styles.
+// Internal helper class used by derived classes to iterate colors, baselines,

[msw, 2015/02/18 23:32:08]

nit: remove "by derived classes" for a one-liner.

[dschuyler, 2015/02/19 00:29:14]

Done.

+// and styles.
 class StyleIterator {
  public:
   StyleIterator(const BreakList<SkColor>& colors,
+                const BreakList<BaselineStyle>& baselines,
                 const std::vector<BreakList<bool> >& styles);
   ~StyleIterator();
 
   // Get the colors and styles at the current iterator position.
   SkColor color() const { return color_->second; }
+  BaselineStyle baseline() const { return baseline_->second; }
   bool style(TextStyle s) const { return style_[s]->second; }
 
   // Get the intersecting range of the current iterator set.
@@ -128,9 +131,11 @@ class StyleIterator {
 
  private:
   BreakList<SkColor> colors_;
+  BreakList<BaselineStyle> baselines_;
   std::vector<BreakList<bool> > styles_;
 
   BreakList<SkColor>::const_iterator color_;
+  BreakList<BaselineStyle>::const_iterator baseline_;
   std::vector<BreakList<bool>::const_iterator> style_;
 
   DISALLOW_COPY_AND_ASSIGN(StyleIterator);
@@ -330,6 +335,11 @@ class GFX_EXPORT RenderText {
   void SetColor(SkColor value);
   void ApplyColor(SkColor value, const Range& range);
 
+  // Set the  baseline style over the entire text or a logical character range.

[msw, 2015/02/18 23:32:08]

nit: remove the extra space before "baseline"

[dschuyler, 2015/02/19 00:29:14]

Done.

+  // The |range| should be valid, non-reversed, and within [0, text().length()].
+  void SetBaselineStyle(BaselineStyle value);
+  void ApplyBaselineStyle(BaselineStyle value, const Range& range);
+
   // Set various text styles over the entire text or a logical character range.
   // The respective |style| is applied if |value| is true, or removed if false.
   // The |range| should be valid, non-reversed, and within [0, text().length()].
@@ -454,6 +464,7 @@ class GFX_EXPORT RenderText {
   bool text_elided() const { return text_elided_; }
 
   const BreakList<SkColor>& colors() const { return colors_; }
+  const BreakList<BaselineStyle>& baselines() const { return baselines_; }
   const std::vector<BreakList<bool> >& styles() const { return styles_; }
 
   const std::vector<internal::Line>& lines() const { return lines_; }
@@ -626,6 +637,13 @@ class GFX_EXPORT RenderText {
   // Updates |layout_text_| and |display_text_| as needed (or marks them dirty).
   void OnTextAttributeChanged();
 
+  // Make sure ranges don't break text graphemes.  If a range in |break_list|
+  // does break a  grapheme in |render_text|, the range will be slightly

[msw, 2015/02/18 23:32:08]

nit: remove the double space before "grapheme".

[dschuyler, 2015/02/19 00:29:14]

Done.

+  // extended to encompass the grapheme.
+  template <typename T>
+  void RestoreBreakList(RenderText* render_text,
+                        T& break_list);
+
   // Elides |text| as needed to fit in the |available_width| using |behavior|.
   // |text_width| is the pre-calculated width of the text shaped by this render
   // text, or pass 0 if the width is unknown.
@@ -690,10 +708,11 @@ class GFX_EXPORT RenderText {
   // Composition text range.
   Range composition_range_;
 
-  // Color and style breaks, used to color and stylize ranges of text.
+  // Color, baseline, and style breaks, used to modify ranges of text.
   // BreakList positions are stored with text indices, not display indices.
   // TODO(msw): Expand to support cursor, selection, background, etc. colors.
   BreakList<SkColor> colors_;
+  BreakList<BaselineStyle> baselines_;
   std::vector<BreakList<bool> > styles_;
 
   // Breaks saved without temporary composition and selection styling.