Return width from drawText to stop re-measure in Canvas

Source/platform/fonts/harfbuzz/FontHarfBuzz.cpp

 /*
  * Copyright (c) 2007, 2008, 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 205 matching lines @@
     if ((textMode & TextModeStroke) && gc->hasStroke()) {
         SkPaint paint = gc->strokePaint();
         gc->adjustTextRenderMode(&paint);
         paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
         if (textMode & TextModeFill)
             paint.setLooper(0);
         gc->drawTextBlob(blob, origin, paint);
     }
 }
 
-void Font::drawComplexText(GraphicsContext* gc, const TextRunPaintInfo& runInfo, const FloatPoint& point) const
+float Font::drawComplexText(GraphicsContext* gc, const TextRunPaintInfo& runInfo, const FloatPoint& point) const
 {
     if (!runInfo.run.length())
-        return;
+        return 0;
 
     TextDrawingModeFlags textMode = gc->textDrawingMode();
     bool fill = textMode & TextModeFill;
     bool stroke = (textMode & TextModeStroke) && gc->hasStroke();
 
     if (!fill && !stroke)
-        return;
+        return 0;
 
     GlyphBuffer glyphBuffer;
     HarfBuzzShaper shaper(this, runInfo.run);
     shaper.setDrawRange(runInfo.from, runInfo.to);
     if (!shaper.shape(&glyphBuffer) || glyphBuffer.isEmpty())
-        return;
+        return 0;
     FloatPoint adjustedPoint = shaper.adjustStartPoint(point);
-    drawGlyphBuffer(gc, runInfo, glyphBuffer, adjustedPoint);
+    return drawGlyphBuffer(gc, runInfo, glyphBuffer, adjustedPoint);
 }
 
 void Font::drawEmphasisMarksForComplexText(GraphicsContext* context, const TextRunPaintInfo& runInfo, const AtomicString& mark, const FloatPoint& point) const
 {
     GlyphBuffer glyphBuffer;
 
     float initialAdvance = getGlyphsAndAdvancesForComplexText(runInfo, glyphBuffer, ForTextEmphasis);
 
     if (glyphBuffer.isEmpty())
         return;
@@ skipping 37 matching lines @@
 FloatRect Font::selectionRectForComplexText(const TextRun& run,
                                             const FloatPoint& point, int height,
                                             int from, int to) const
 {
     HarfBuzzShaper shaper(this, run);
     if (!shaper.shape())
         return FloatRect();
     return shaper.selectionRect(point, height, from, to);
 }
 
-PassTextBlobPtr Font::buildTextBlob(const GlyphBuffer& glyphBuffer, float initialAdvance, const FloatRect& bounds) const
+PassTextBlobPtr Font::buildTextBlob(const GlyphBuffer& glyphBuffer, float initialAdvance, const FloatRect& bounds, float& advance) const
 {
     // FIXME: Except for setupPaint, this is not specific to FontHarfBuzz.
     // FIXME: Also implement the more general full-positioning path.
     ASSERT(!glyphBuffer.hasVerticalAdvances());
 
     SkTextBlobBuilder builder;
     SkScalar x = SkFloatToScalar(initialAdvance);
     SkRect skBounds = bounds;
 
     unsigned i = 0;
@@ skipping 25 matching lines @@
         const uint16_t* glyphs = glyphBuffer.glyphs(start);
         std::copy(glyphs, glyphs + count, buffer.glyphs);
 
         const FloatSize* advances = glyphBuffer.advances(start);
         for (unsigned j = 0; j < count; j++) {
             buffer.pos[j] = x;
             x += SkFloatToScalar(advances[j].width());
         }
     }
 
+    advance = x;
     return adoptRef(builder.build());
 }
 
 } // namespace blink