Return width from drawText to stop re-measure in Canvas

Source/platform/fonts/Font.h

Index: Source/platform/fonts/Font.h
diff --git a/Source/platform/fonts/Font.h b/Source/platform/fonts/Font.h
index 832ddad4cb2cd9070c65d9129c66064b09da4670..212811d27faf0979840c5bd447e60cda27a58f19 100644
--- a/Source/platform/fonts/Font.h
+++ b/Source/platform/fonts/Font.h
@@ -100,7 +100,7 @@ public:
     void update(PassRefPtrWillBeRawPtr<FontSelector>) const;
 
     enum CustomFontNotReadyAction { DoNotPaintIfFontNotReady, UseFallbackIfFontNotReady };
-    void drawText(GraphicsContext*, const TextRunPaintInfo&, const FloatPoint&, CustomFontNotReadyAction = DoNotPaintIfFontNotReady) const;
+    float 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;
@@ -140,10 +140,10 @@ private:
 
     // Returns the initial in-stream advance.
     float getGlyphsAndAdvancesForSimpleText(const TextRunPaintInfo&, GlyphBuffer&, ForTextEmphasisOrNot = NotForTextEmphasis) const;
-    void drawSimpleText(GraphicsContext*, const TextRunPaintInfo&, const FloatPoint&) const;
+    float 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&, unsigned from, unsigned numGlyphs, const FloatPoint&, const FloatRect& textRect) const;
-    void drawGlyphBuffer(GraphicsContext*, const TextRunPaintInfo&, const GlyphBuffer&, const FloatPoint&) const;
+    float drawGlyphBuffer(GraphicsContext*, const TextRunPaintInfo&, const GlyphBuffer&, const FloatPoint&) const;
     void drawTextBlob(GraphicsContext*, const SkTextBlob*, const SkPoint& origin) const;
     void drawEmphasisMarks(GraphicsContext*, const TextRunPaintInfo&, const GlyphBuffer&, const AtomicString&, const FloatPoint&) const;
     float floatWidthForSimpleText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, IntRectExtent* glyphBounds = 0) const;
@@ -154,7 +154,7 @@ private:
 
     // Returns the initial in-stream advance.
     float getGlyphsAndAdvancesForComplexText(const TextRunPaintInfo&, GlyphBuffer&, ForTextEmphasisOrNot = NotForTextEmphasis) const;
-    void drawComplexText(GraphicsContext*, const TextRunPaintInfo&, const FloatPoint&) const;
+    float 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, IntRectExtent* glyphBounds) const;
     int offsetForPositionForComplexText(const TextRun&, float position, bool includePartialGlyphs) const;
@@ -187,7 +187,7 @@ private:
         return m_fontFallbackList && m_fontFallbackList->shouldSkipDrawing();
     }
 
-    PassTextBlobPtr buildTextBlob(const GlyphBuffer&, float initialAdvance, const FloatRect& bounds) const;
+    PassTextBlobPtr buildTextBlob(const GlyphBuffer&, float initialAdvance, const FloatRect& bounds, float& advance) const;
 
     FontDescription m_fontDescription;
     mutable RefPtr<FontFallbackList> m_fontFallbackList;