Invalidation not taking glyph bounds into account on HarfBuzz path

Source/platform/fonts/harfbuzz/HarfBuzzShaper.cpp

Index: Source/platform/fonts/harfbuzz/HarfBuzzShaper.cpp
diff --git a/Source/platform/fonts/harfbuzz/HarfBuzzShaper.cpp b/Source/platform/fonts/harfbuzz/HarfBuzzShaper.cpp
index 9c31b529473cb085f0e6381d47fd4dd724ca95c1..7fe46ff5c0432be1388427d7d3e6859ab7ac2e7d 100644
--- a/Source/platform/fonts/harfbuzz/HarfBuzzShaper.cpp
+++ b/Source/platform/fonts/harfbuzz/HarfBuzzShaper.cpp
@@ -382,6 +382,10 @@ HarfBuzzShaper::HarfBuzzShaper(const Font* font, const TextRun& run, ForTextEmph
     , 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_normalizedBuffer = adoptArrayPtr(new UChar[m_run.length() + 1]);
     normalizeCharacters(m_run, m_run.length(), m_normalizedBuffer.get(), &m_normalizedBufferLength);
@@ -865,6 +869,7 @@ void HarfBuzzShaper::setGlyphPositionsForHarfBuzzRun(HarfBuzzRun* currentRun, hb
     unsigned numGlyphs = currentRun->numGlyphs();
     uint16_t* glyphToCharacterIndexes = currentRun->glyphToCharacterIndexes();
     float totalAdvance = 0;
+    FloatPoint glyphOrigin;
 
     // HarfBuzz returns the shaping result in visual order. We need not to flip for RTL.
     for (size_t i = 0; i < numGlyphs; ++i) {
@@ -901,6 +906,14 @@ void HarfBuzzShaper::setGlyphPositionsForHarfBuzzRun(HarfBuzzRun* currentRun, hb
 
         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());
+        glyphOrigin += FloatSize(advance + offsetX, offsetY);
+
         totalAdvance += advance;
     }
     currentRun->setWidth(totalAdvance > 0.0 ? totalAdvance : 0.0);