Track the region where text is painted.

Source/core/platform/graphics/Font.h

Index: Source/core/platform/graphics/Font.h
diff --git a/Source/core/platform/graphics/Font.h b/Source/core/platform/graphics/Font.h
index d7858e77f647349819c21720e93c9e13d02b4ba6..1261b64e868999b625ea40319b9cbc64ae65ad82 100644
--- a/Source/core/platform/graphics/Font.h
+++ b/Source/core/platform/graphics/Font.h
@@ -54,6 +54,7 @@ class GraphicsContext;
 class RenderText;
 class TextLayout;
 class TextRun;
+struct TextRunPaintInfo;
 
 struct GlyphData;
 
@@ -97,8 +98,8 @@ public:
     void update(PassRefPtr<FontSelector>) const;
 
     enum CustomFontNotReadyAction { DoNotPaintIfFontNotReady, UseFallbackIfFontNotReady };
-    void drawText(GraphicsContext*, const TextRun&, const FloatPoint&, int from = 0, int to = -1, CustomFontNotReadyAction = DoNotPaintIfFontNotReady) const;
-    void drawEmphasisMarks(GraphicsContext*, const TextRun&, const AtomicString& mark, const FloatPoint&, int from = 0, int to = -1) const;
+    void drawText(GraphicsContext*, const TextRunPaintInfo&, const FloatPoint&, CustomFontNotReadyAction = DoNotPaintIfFontNotReady) const;
+    void drawEmphasisMarks(GraphicsContext*, const TextRunPaintInfo&, const AtomicString& mark, const FloatPoint&) const;
 
     float width(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, GlyphOverflow* = 0) const;
     float width(const TextRun&, int& charsConsumed, String& glyphName) const;
@@ -173,11 +174,11 @@ private:
 
     // Returns the initial in-stream advance.
     float getGlyphsAndAdvancesForSimpleText(const TextRun&, int from, int to, GlyphBuffer&, ForTextEmphasisOrNot = NotForTextEmphasis) const;
-    void drawSimpleText(GraphicsContext*, const TextRun&, const FloatPoint&, int from, int to) const;
-    void drawEmphasisMarksForSimpleText(GraphicsContext*, const TextRun&, const AtomicString& mark, const FloatPoint&, int from, int to) const;
-    void drawGlyphs(GraphicsContext*, const SimpleFontData*, const GlyphBuffer&, int from, int to, const FloatPoint&) const;
-    void drawGlyphBuffer(GraphicsContext*, const TextRun&, const GlyphBuffer&, const FloatPoint&) const;
-    void drawEmphasisMarks(GraphicsContext*, const TextRun&, const GlyphBuffer&, const AtomicString&, const FloatPoint&) const;
+    void drawSimpleText(GraphicsContext*, const TextRunPaintInfo&, const FloatPoint&) const;
+    void drawEmphasisMarksForSimpleText(GraphicsContext*, const TextRunPaintInfo&, const AtomicString& mark, const FloatPoint&) const;
+    void drawGlyphs(GraphicsContext*, const SimpleFontData*, const GlyphBuffer&, int from, int to, const FloatPoint&, const FloatRect& textRect) const;
+    void drawGlyphBuffer(GraphicsContext*, const TextRunPaintInfo&, const GlyphBuffer&, const FloatPoint&) const;
+    void drawEmphasisMarks(GraphicsContext*, const TextRunPaintInfo&, const GlyphBuffer&, const AtomicString&, const FloatPoint&) const;
     float floatWidthForSimpleText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, GlyphOverflow* = 0) const;
     int offsetForPositionForSimpleText(const TextRun&, float position, bool includePartialGlyphs) const;
     FloatRect selectionRectForSimpleText(const TextRun&, const FloatPoint&, int h, int from, int to) const;
@@ -189,8 +190,8 @@ private:
 
     // Returns the initial in-stream advance.
     float getGlyphsAndAdvancesForComplexText(const TextRun&, int from, int to, GlyphBuffer&, ForTextEmphasisOrNot = NotForTextEmphasis) const;
-    void drawComplexText(GraphicsContext*, const TextRun&, const FloatPoint&, int from, int to) const;
-    void drawEmphasisMarksForComplexText(GraphicsContext*, const TextRun&, const AtomicString& mark, const FloatPoint&, int from, int to) const;
+    void drawComplexText(GraphicsContext*, const TextRunPaintInfo&, const FloatPoint&) const;
+    void drawEmphasisMarksForComplexText(GraphicsContext*, const TextRunPaintInfo&, const AtomicString& mark, const FloatPoint&) const;
     float floatWidthForComplexText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, GlyphOverflow* = 0) const;
     int offsetForPositionForComplexText(const TextRun&, float position, bool includePartialGlyphs) const;
     FloatRect selectionRectForComplexText(const TextRun&, const FloatPoint&, int h, int from, int to) const;