Revert of Remove unused FontPlatformDataHarfBuzz::emSizeInFontUnits

Source/platform/fonts/harfbuzz/FontPlatformDataHarfBuzz.cpp

 /*
  * Copyright (c) 2006, 2007, 2008, 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 61 matching lines @@
     useSkiaAntiAlias = useAntiAlias;
 }
 
 void FontPlatformData::setSubpixelRendering(bool useSubpixelRendering)
 {
     useSkiaSubpixelRendering = useSubpixelRendering;
 }
 
 FontPlatformData::FontPlatformData(WTF::HashTableDeletedValueType)
     : m_textSize(0)
+    , m_emSizeInFontUnits(0)
     , m_syntheticBold(false)
     , m_syntheticItalic(false)
     , m_orientation(Horizontal)
     , m_isHashTableDeletedValue(true)
 {
 }
 
 FontPlatformData::FontPlatformData()
     : m_textSize(0)
+    , m_emSizeInFontUnits(0)
     , m_syntheticBold(false)
     , m_syntheticItalic(false)
     , m_orientation(Horizontal)
     , m_isHashTableDeletedValue(false)
 {
 }
 
 FontPlatformData::FontPlatformData(float textSize, bool syntheticBold, bool syntheticItalic)
     : m_textSize(textSize)
+    , m_emSizeInFontUnits(0)
     , m_syntheticBold(syntheticBold)
     , m_syntheticItalic(syntheticItalic)
     , m_orientation(Horizontal)
     , m_isHashTableDeletedValue(false)
 {
 }
 
 FontPlatformData::FontPlatformData(const FontPlatformData& src)
     : m_typeface(src.m_typeface)
     , m_family(src.m_family)
     , m_textSize(src.m_textSize)
+    , m_emSizeInFontUnits(src.m_emSizeInFontUnits)
     , m_syntheticBold(src.m_syntheticBold)
     , m_syntheticItalic(src.m_syntheticItalic)
     , m_orientation(src.m_orientation)
     , m_style(src.m_style)
     , m_harfBuzzFace(nullptr)
     , m_isHashTableDeletedValue(false)
 {
 }
 
 FontPlatformData::FontPlatformData(PassRefPtr<SkTypeface> tf, const char* family, float textSize, bool syntheticBold, bool syntheticItalic, FontOrientation orientation, bool subpixelTextPosition)
     : m_typeface(tf)
     , m_family(family)
     , m_textSize(textSize)
+    , m_emSizeInFontUnits(0)
     , m_syntheticBold(syntheticBold)
     , m_syntheticItalic(syntheticItalic)
     , m_orientation(orientation)
     , m_isHashTableDeletedValue(false)
 {
     querySystemForRenderStyle(subpixelTextPosition);
 }
 
 FontPlatformData::FontPlatformData(const FontPlatformData& src, float textSize)
     : m_typeface(src.m_typeface)
     , m_family(src.m_family)
     , m_textSize(textSize)
+    , m_emSizeInFontUnits(src.m_emSizeInFontUnits)
     , m_syntheticBold(src.m_syntheticBold)
     , m_syntheticItalic(src.m_syntheticItalic)
     , m_orientation(src.m_orientation)
     , m_harfBuzzFace(nullptr)
     , m_isHashTableDeletedValue(false)
 {
     querySystemForRenderStyle(FontDescription::subpixelPositioning());
 }
 
 FontPlatformData::~FontPlatformData()
 {
 }
 
+int FontPlatformData::emSizeInFontUnits() const
+{
+    if (m_emSizeInFontUnits)
+        return m_emSizeInFontUnits;
+
+    m_emSizeInFontUnits = m_typeface->getUnitsPerEm();
+    return m_emSizeInFontUnits;
+}
+
 FontPlatformData& FontPlatformData::operator=(const FontPlatformData& src)
 {
     m_typeface = src.m_typeface;
     m_family = src.m_family;
     m_textSize = src.m_textSize;
     m_syntheticBold = src.m_syntheticBold;
     m_syntheticItalic = src.m_syntheticItalic;
     m_harfBuzzFace = nullptr;
     m_orientation = src.m_orientation;
     m_style = src.m_style;
+    m_emSizeInFontUnits = src.m_emSizeInFontUnits;
 
     return *this;
 }
 
 #ifndef NDEBUG
 String FontPlatformData::description() const
 {
     return String();
 }
 #endif
@@ skipping 110 matching lines @@
     if (m_style.useSubpixelRendering == FontRenderStyle::NoPreference)
         m_style.useSubpixelRendering = useSkiaSubpixelRendering;
 
     // TestRunner specifically toggles the subpixel positioning flag.
     if (m_style.useSubpixelPositioning == FontRenderStyle::NoPreference
         || isRunningLayoutTest())
         m_style.useSubpixelPositioning = useSkiaSubpixelPositioning;
 }
 
 } // namespace WebCore