Revert of Use removeFontFace to avoid resetting fontSelector.

Source/core/dom/TreeScopeStyleSheetCollection.cpp

Index: Source/core/dom/TreeScopeStyleSheetCollection.cpp
diff --git a/Source/core/dom/TreeScopeStyleSheetCollection.cpp b/Source/core/dom/TreeScopeStyleSheetCollection.cpp
index ea7eef7709c80b88fa40a953614228201983e27e..e53f441b87272714a1a8b1bfeb950b8e7d651263 100644
--- a/Source/core/dom/TreeScopeStyleSheetCollection.cpp
+++ b/Source/core/dom/TreeScopeStyleSheetCollection.cpp
@@ -121,19 +121,24 @@
     return false;
 }
 
-static bool findFontFaceRulesFromStyleSheetContents(Vector<StyleSheetContents*> sheets, Vector<const StyleRuleFontFace*>& fontFaceRules)
-{
-    bool hasFontFaceRule = false;
-
+static bool styleSheetContentsHasFontFaceRule(Vector<StyleSheetContents*> sheets)
+{
     for (unsigned i = 0; i < sheets.size(); ++i) {
         ASSERT(sheets[i]);
-        if (sheets[i]->hasFontFaceRule()) {
-            // FIXME: We don't need this for styles in shadow tree.
-            sheets[i]->findFontFaceRules(fontFaceRules);
-            hasFontFaceRule = true;
-        }
-    }
-    return hasFontFaceRule;
+        if (sheets[i]->hasFontFaceRule())
+            return true;
+    }
+    return false;
+}
+
+static bool cssStyleSheetHasFontFaceRule(const Vector<RefPtr<CSSStyleSheet> > sheets)
+{
+    for (unsigned i = 0; i < sheets.size(); ++i) {
+        ASSERT(sheets[i]);
+        if (sheets[i]->contents()->hasFontFaceRule())
+            return true;
+    }
+    return false;
 }
 
 void TreeScopeStyleSheetCollection::analyzeStyleSheetChange(StyleResolverUpdateMode updateMode, const StyleSheetCollection& newCollection, StyleSheetChange& change)
@@ -153,10 +158,18 @@
         if (updateType != Additive) {
             change.styleResolverUpdateType = updateType;
         } else {
-            change.styleResolverUpdateType = Reset;
-            // If @font-face is removed, needs full style recalc.
-            if (findFontFaceRulesFromStyleSheetContents(addedSheets, change.fontFaceRulesToRemove))
+            if (styleSheetContentsHasFontFaceRule(addedSheets)) {
+                change.styleResolverUpdateType = ResetStyleResolverAndFontSelector;
                 return;
+            }
+            // FIXME: since currently all stylesheets are re-added after reseting styleresolver,
+            // fontSelector should be always reset. After creating RuleSet for each StyleSheetContents,
+            // we can avoid appending all stylesheetcontents in reset case.
+            // So we can remove "styleSheetContentsHasFontFaceRule(newSheets)".
+            if (cssStyleSheetHasFontFaceRule(newCollection.activeAuthorStyleSheets()))
+                change.styleResolverUpdateType = ResetStyleResolverAndFontSelector;
+            else
+                change.styleResolverUpdateType = Reset;
         }
     }