Use removeFontFace to avoid resetting fontSelector.

Source/core/css/CSSSegmentedFontFaceCache.cpp

Index: Source/core/css/CSSSegmentedFontFaceCache.cpp
diff --git a/Source/core/css/CSSSegmentedFontFaceCache.cpp b/Source/core/css/CSSSegmentedFontFaceCache.cpp
index a12f78d3dccecc4af98345522cea6d4674f2d751..8f5d03ef1396f66e3d9d324fec54872f47a34536 100644
--- a/Source/core/css/CSSSegmentedFontFaceCache.cpp
+++ b/Source/core/css/CSSSegmentedFontFaceCache.cpp
@@ -109,6 +109,13 @@ void CSSSegmentedFontFaceCache::removeCSSFontFace(CSSFontFace* cssFontFace, bool
     ++m_version;
 }
 
+void CSSSegmentedFontFaceCache::clear()
+{
+    for (StyleRuleToFontFace::iterator it = m_styleRuleToFontFace.begin(); it != m_styleRuleToFontFace.end(); ++it)
+        removeCSSFontFace(it->value.get(), true);
+    m_styleRuleToFontFace.clear();
+}
+
 static inline bool compareFontFaces(CSSSegmentedFontFace* first, CSSSegmentedFontFace* second, FontTraitsMask desiredTraitsMask)
 {
     FontTraitsMask firstTraitsMask = first->traitsMask();