fontSelector should be reset when removing stylesheets which has @font-face rule.

Source/core/dom/StyleSheetCollection.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 11 matching lines @@
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "config.h"
 #include "core/dom/StyleSheetCollection.h"
 
 #include "core/css/CSSStyleSheet.h"
 #include "core/css/StyleInvalidationAnalysis.h"
+#include "core/css/StyleRuleImport.h"
 #include "core/css/StyleSheetContents.h"
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/StyleEngine.h"
 #include "core/html/HTMLStyleElement.h"
 #include "core/page/Settings.h"
 
 namespace WebCore {
 
@@ skipping 71 matching lines @@
             hasActiveLoadingStylesheet = true;
     }
     if (m_hadActiveLoadingStylesheet && !hasActiveLoadingStylesheet) {
         m_hadActiveLoadingStylesheet = false;
         return true;
     }
     m_hadActiveLoadingStylesheet = hasActiveLoadingStylesheet;
     return false;
 }
 
-void StyleSheetCollection::analyzeStyleSheetChange(StyleResolverUpdateMode updateMode, const Vector<RefPtr<CSSStyleSheet> >& oldStyleSheets, const Vector<RefPtr<CSSStyleSheet> >& newStyleSheets, StyleResolverUpdateType& styleResolverUpdateType, bool& requiresFullStyleRecalc)
+static bool styleSheetContentsHasFontFaceRule(Vector<StyleSheetContents*> sheets)
 {
-    styleResolverUpdateType = Reconstruct;
-    requiresFullStyleRecalc = true;
+    for (unsigned i =  0; i < sheets.size(); ++i) {
+        ASSERT(sheets[i]);
+        if (sheets[i]->hasFontFaceRule())
+            return true;
+    }
+    return false;
+}
 
+void StyleSheetCollection::analyzeStyleSheetChange(StyleResolverUpdateMode updateMode, const Vector<RefPtr<CSSStyleSheet> >& oldStyleSheets, const Vector<RefPtr<CSSStyleSheet> >& newStyleSheets, StyleSheetChange& change)
+{
     if (activeLoadingStyleSheetLoaded(newStyleSheets))
         return;
 
     if (updateMode != AnalyzedStyleUpdate)
         return;
     if (!document()->styleResolverIfExists())
         return;
 
     // Find out which stylesheets are new.
     Vector<StyleSheetContents*> addedSheets;
     if (oldStyleSheets.size() <= newStyleSheets.size()) {
-        styleResolverUpdateType = compareStyleSheets(oldStyleSheets, newStyleSheets, addedSheets);
+        change.styleResolverUpdateType = compareStyleSheets(oldStyleSheets, newStyleSheets, addedSheets);
     } else {
         StyleResolverUpdateType updateType = compareStyleSheets(newStyleSheets, oldStyleSheets, addedSheets);
-        styleResolverUpdateType = updateType != Additive ? updateType : Reset;
+        if (updateType != Additive) {
+            change.styleResolverUpdateType = updateType;
+        } else {
+            if (styleSheetContentsHasFontFaceRule(addedSheets)) {
+                change.styleResolverUpdateType = ResetStyleResolverAndFontSelector;
+                return;
+            }
+            change.styleResolverUpdateType = Reset;
+        }
     }
 
     // FIXME: If styleResolverUpdateType is still Reconstruct, we could return early here
     // as destroying the StyleResolver will recalc the whole document anyway?
 
     // If we are already parsing the body and so may have significant amount of elements, put some effort into trying to avoid style recalcs.
     if (!document()->body() || document()->hasNodesWithPlaceholderStyle())
         return;
     StyleInvalidationAnalysis invalidationAnalysis(addedSheets);
     if (invalidationAnalysis.dirtiesAllStyle())
         return;
     invalidationAnalysis.invalidateStyle(*document());
-    requiresFullStyleRecalc = false;
+    change.requiresFullStyleRecalc = false;
+    return;
 }
 
 void StyleSheetCollection::resetAllRuleSetsInTreeScope(StyleResolver* styleResolver)
 {
     // FIXME: If many web developers use style scoped, implement reset RuleSets in per-scoping node manner.
     if (DocumentOrderedList* styleScopedScopingNodes = scopingNodesForStyleScoped()) {
         for (DocumentOrderedList::iterator it = styleScopedScopingNodes->begin(); it != styleScopedScopingNodes->end(); ++it)
             styleResolver->resetAuthorStyle(toContainerNode(*it));
     }
     if (ListHashSet<Node*, 4>* removedNodes = scopingNodesRemoved()) {
@@ skipping 11 matching lines @@
     }
     return false;
 }
 
 void StyleSheetCollection::updateUsesRemUnits()
 {
     m_usesRemUnits = styleSheetsUseRemUnits(m_activeAuthorStyleSheets);
 }
 
 }