Change HarfBuzzShaper to use FloatBoxExtent for glyp bounds

Source/platform/fonts/harfbuzz/HarfBuzzShaper.cpp

 /*
  * Copyright (c) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 BlackBerry Limited. 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.
@@ skipping 364 matching lines @@
     , m_normalizedBufferLength(0)
     , m_run(run)
     , m_wordSpacingAdjustment(font->fontDescription().wordSpacing())
     , m_padding(0)
     , m_padPerWordBreak(0)
     , m_padError(0)
     , m_letterSpacing(font->fontDescription().letterSpacing())
     , m_fromIndex(0)
     , m_toIndex(m_run.length())
     , m_forTextEmphasis(forTextEmphasis)
-    , m_minGlyphBoundingBoxX(std::numeric_limits<float>::max())
-    , m_maxGlyphBoundingBoxX(std::numeric_limits<float>::min())
-    , m_minGlyphBoundingBoxY(std::numeric_limits<float>::max())
-    , m_maxGlyphBoundingBoxY(std::numeric_limits<float>::min())
+    , m_glyphBoundingBox(std::numeric_limits<float>::max(), std::numeric_limits<float>::min(), std::numeric_limits<float>::min(), std::numeric_limits<float>::max())
 {
     m_normalizedBuffer = adoptArrayPtr(new UChar[m_run.length() + 1]);
     normalizeCharacters(m_run, m_run.length(), m_normalizedBuffer.get(), &m_normalizedBufferLength);
     setPadding(m_run.expansion());
     setFontFeatures();
 }
 
 bool HarfBuzzShaper::isWordEnd(unsigned index)
 {
     // This could refer a high-surrogate, but should work.
@@ skipping 500 matching lines @@
             // In RTL, spacing should be added to left side of glyphs.
             offsetX += spacing;
             if (!isClusterEnd)
                 offsetX += m_letterSpacing;
         }
 
         currentRun->setGlyphAndPositions(i, glyph, advance, offsetX, offsetY);
 
         FloatRect glyphBounds = currentFontData->boundsForGlyph(glyph);
         glyphBounds.move(glyphOrigin.x(), glyphOrigin.y());
-        m_minGlyphBoundingBoxX = std::min(m_minGlyphBoundingBoxX, glyphBounds.x());
-        m_maxGlyphBoundingBoxX = std::max(m_maxGlyphBoundingBoxX, glyphBounds.maxX());
-        m_minGlyphBoundingBoxY = std::min(m_minGlyphBoundingBoxY, glyphBounds.y());
-        m_maxGlyphBoundingBoxY = std::max(m_maxGlyphBoundingBoxY, glyphBounds.maxY());
+        m_glyphBoundingBox.unite(glyphBounds);
         glyphOrigin += FloatSize(advance + offsetX, offsetY);
 
         totalAdvance += advance;
     }
     currentRun->setWidth(totalAdvance > 0.0 ? totalAdvance : 0.0);
     m_totalWidth += currentRun->width();
 }
 
 void HarfBuzzShaper::fillGlyphBufferFromHarfBuzzRun(GlyphBuffer* glyphBuffer, HarfBuzzRun* currentRun, FloatPoint& firstOffsetOfNextRun)
 {
@@ skipping 175 matching lines @@
     if (!foundToX)
         toX = m_run.rtl() ? 0 : m_totalWidth;
 
     // Using floorf() and roundf() as the same as mac port.
     if (fromX < toX)
         return FloatRect(floorf(point.x() + fromX), point.y(), roundf(toX - fromX), height);
     return FloatRect(floorf(point.x() + toX), point.y(), roundf(fromX - toX), height);
 }
 
 } // namespace WebCore