Use removeFontFace to avoid resetting fontSelector.

Source/core/dom/StyleEngine.h

Index: Source/core/dom/StyleEngine.h
diff --git a/Source/core/dom/StyleEngine.h b/Source/core/dom/StyleEngine.h
index b3fe260a4cff6aad5c8d8de62a66eb4c4b2d9716..265f999fb52a7d2aa22d01dd496328512d9123f3 100644
--- a/Source/core/dom/StyleEngine.h
+++ b/Source/core/dom/StyleEngine.h
@@ -48,6 +48,7 @@ class Node;
 class RuleFeatureSet;
 class ShadowTreeStyleSheetCollection;
 class StyleResolver;
+class StyleRuleFontFace;
 class StyleSheet;
 class StyleSheetCollection;
 class StyleSheetContents;
@@ -169,6 +170,8 @@ public:
     void clearMasterResolver();
 
     CSSFontSelector* fontSelector() { return m_fontSelector.get(); }
+    void removeFontFaceRules(const Vector<const StyleRuleFontFace*>&);
+    // FIXME: still need to use resetFontSelector when GenericFontFamilySettings is changed.
     void resetFontSelector();
 
     void didAttach();