Use removeFontFace to avoid resetting fontSelector.

Source/core/dom/DocumentStyleSheetCollection.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
@@ skipping 117 matching lines @@
 bool DocumentStyleSheetCollection::updateActiveStyleSheets(StyleEngine* engine, StyleResolverUpdateMode updateMode)
 {
     DocumentStyleSheetCollector collector(m_treeScope);
     collectStyleSheets(engine, collector);
 
     StyleSheetChange change;
     analyzeStyleSheetChange(updateMode, collector.collection(), change);
 
     if (change.styleResolverUpdateType == Reconstruct) {
         engine->clearMasterResolver();
+        // FIMXE: The following depends on whether StyleRuleFontFace was modified or not.
+        // No need to always-reset.
         engine->resetFontSelector();
     } else if (StyleResolver* styleResolver = engine->resolver()) {
         // FIXME: We might have already had styles in child treescope. In this case, we cannot use buildScopedStyleTreeInDocumentOrder.
         // Need to change "false" to some valid condition.
         styleResolver->setBuildScopedStyleTreeInDocumentOrder(false);
         if (change.styleResolverUpdateType != Additive) {
-            ASSERT(change.styleResolverUpdateType == Reset || change.styleResolverUpdateType == ResetStyleResolverAndFontSelector);
+            ASSERT(change.styleResolverUpdateType == Reset);
             resetAllRuleSetsInTreeScope(styleResolver);
-            if (change.styleResolverUpdateType == ResetStyleResolverAndFontSelector)
-                engine->resetFontSelector();
+            engine->removeFontFaceRules(change.fontFaceRulesToRemove);
             styleResolver->removePendingAuthorStyleSheets(m_activeAuthorStyleSheets);
             styleResolver->lazyAppendAuthorStyleSheets(0, collector.collection().activeAuthorStyleSheets());
         } else {
             styleResolver->lazyAppendAuthorStyleSheets(m_activeAuthorStyleSheets.size(), collector.collection().activeAuthorStyleSheets());
         }
-    } else if (change.styleResolverUpdateType == ResetStyleResolverAndFontSelector) {
-        engine->resetFontSelector();
     }
     m_scopingNodesForStyleScoped.didRemoveScopingNodes();
     collector.setCollectionTo(*this);
     updateUsesRemUnits();
 
     return change.requiresFullStyleRecalc;
 }
 
 }