Explicitly compare FontVariant to enumerators.

Source/platform/fonts/WidthIterator.cpp

Index: Source/platform/fonts/WidthIterator.cpp
diff --git a/Source/platform/fonts/WidthIterator.cpp b/Source/platform/fonts/WidthIterator.cpp
index 772fdb9a7132a50b4b00a11c33560a82c5c0f363..4775b50094e4ce8adf140433e1bb14d899d16000 100644
--- a/Source/platform/fonts/WidthIterator.cpp
+++ b/Source/platform/fonts/WidthIterator.cpp
@@ -184,9 +184,10 @@ inline unsigned WidthIterator::advanceInternal(TextIterator& textIterator, Glyph
             if (m_fallbackFonts && fontData != primaryFont) {
                 // FIXME: This does a little extra work that could be avoided if
                 // glyphDataForCharacter() returned whether it chose to use a small caps font.
-                if (!m_font->fontDescription().variant() || character == toUpper(character))
+                if (m_font->fontDescription().variant() == FontVariantNormal || character == toUpper(character))
                     m_fallbackFonts->add(fontData);
                 else {
+                    ASSERT(m_font->fontDescription().variant() == FontVariantSmallCaps);
                     const GlyphData& uppercaseGlyphData = m_font->glyphDataForCharacter(toUpper(character), rtl);
                     if (uppercaseGlyphData.fontData != primaryFont)
                         m_fallbackFonts->add(uppercaseGlyphData.fontData);