Revert of Remove unused FontPlatformDataHarfBuzz::emSizeInFontUnits...

Revert of Remove unused FontPlatformDataHarfBuzz::emSizeInFontUnits (https://codereview.chromium.org/210573002/)

Reason for revert:
This might have caused android tests failure: 
http://build.chromium.org/p/chromium.webkit/builders/Android%20Tests%20%28dbg%29/builds/18266
Speculatively reverting it.

Original issue's description:
> Remove unused FontPlatformDataHarfBuzz::emSizeInFontUnits
> 
> Remove the unused m_emSizeInFontUnits field and emSizeInFontUnits
> method from FontPlatformDataHarfBuzz.
> 
> BUG=355806
> R=pdr@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=169955

TBR=pdr@chromium.org,dglazkov@chromium.org,eae@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=355806

Review URL: https://codereview.chromium.org/212763002

git-svn-id: svn://svn.chromium.org/blink/trunk@170048 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/platform/fonts/harfbuzz/FontPlatformDataHarfBuzz.cpp

@@ -79,6 +79,7 @@ void FontPlatformData::setSubpixelRendering(bool useSubpixelRendering)
 
 FontPlatformData::FontPlatformData(WTF::HashTableDeletedValueType)
     : m_textSize(0)
+    , m_emSizeInFontUnits(0)
     , m_syntheticBold(false)
     , m_syntheticItalic(false)
     , m_orientation(Horizontal)
@@ -88,6 +89,7 @@ FontPlatformData::FontPlatformData(WTF::HashTableDeletedValueType)
 
 FontPlatformData::FontPlatformData()
     : m_textSize(0)
+    , m_emSizeInFontUnits(0)
     , m_syntheticBold(false)
     , m_syntheticItalic(false)
     , m_orientation(Horizontal)
@@ -97,6 +99,7 @@ FontPlatformData::FontPlatformData()
 
 FontPlatformData::FontPlatformData(float textSize, bool syntheticBold, bool syntheticItalic)
     : m_textSize(textSize)
+    , m_emSizeInFontUnits(0)
     , m_syntheticBold(syntheticBold)
     , m_syntheticItalic(syntheticItalic)
     , m_orientation(Horizontal)
@@ -108,6 +111,7 @@ 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)
@@ -121,6 +125,7 @@ FontPlatformData::FontPlatformData(PassRefPtr<SkTypeface> tf, const char* family
     : m_typeface(tf)
     , m_family(family)
     , m_textSize(textSize)
+    , m_emSizeInFontUnits(0)
     , m_syntheticBold(syntheticBold)
     , m_syntheticItalic(syntheticItalic)
     , m_orientation(orientation)
@@ -133,6 +138,7 @@ 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)
@@ -146,6 +152,15 @@ 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;
@@ -156,6 +171,7 @@ FontPlatformData& FontPlatformData::operator=(const FontPlatformData& src)
     m_harfBuzzFace = nullptr;
     m_orientation = src.m_orientation;
     m_style = src.m_style;
+    m_emSizeInFontUnits = src.m_emSizeInFontUnits;
 
     return *this;
 }

third_party/WebKit/Source/platform/fonts/harfbuzz/FontPlatformDataHarfBuzz.h

@@ -93,6 +93,7 @@ public:
 
     unsigned hash() const;
     float size() const { return m_textSize; }
+    int emSizeInFontUnits() const;
 
     FontOrientation orientation() const { return m_orientation; }
     void setOrientation(FontOrientation orientation) { m_orientation = orientation; }
@@ -132,6 +133,7 @@ private:
     RefPtr<SkTypeface> m_typeface;
     CString m_family;
     float m_textSize;
+    mutable int m_emSizeInFontUnits;
     bool m_syntheticBold;
     bool m_syntheticItalic;
     FontOrientation m_orientation;