Use removeFontFace to avoid resetting fontSelector.

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 134 matching lines @@
             hasActiveLoadingStylesheet = true;
     }
     if (m_hadActiveLoadingStylesheet && !hasActiveLoadingStylesheet) {
         m_hadActiveLoadingStylesheet = false;
         return true;
     }
     m_hadActiveLoadingStylesheet = hasActiveLoadingStylesheet;
     return false;
 }
 
-static bool styleSheetContentsHasFontFaceRule(Vector<StyleSheetContents*> sheets)
+static bool findFontFaceRulesFromStyleSheetContents(Vector<StyleSheetContents*> sheets, Vector<const StyleRuleFontFace*>& fontFaceRules)
 {
+    bool hasFontFaceRule = false;
+
     for (unsigned i = 0; i < sheets.size(); ++i) {
         ASSERT(sheets[i]);
-        if (sheets[i]->hasFontFaceRule())
-            return true;
+        if (sheets[i]->hasFontFaceRule()) {
+            // FIXME: We don't need this for styles in shadow tree.
+            sheets[i]->findFontFaceRules(fontFaceRules);
+            hasFontFaceRule = 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;
+    return hasFontFaceRule;
 }
 
 void StyleSheetCollection::analyzeStyleSheetChange(StyleResolverUpdateMode updateMode, const StyleSheetCollectionBase& newCollection, StyleSheetChange& change)
 {
     if (activeLoadingStyleSheetLoaded(newCollection.activeAuthorStyleSheets()))
         return;
 
     if (updateMode != AnalyzedStyleUpdate)
         return;
 
     // Find out which stylesheets are new.
     Vector<StyleSheetContents*> addedSheets;
     if (m_activeAuthorStyleSheets.size() <= newCollection.activeAuthorStyleSheets().size()) {
         change.styleResolverUpdateType = compareStyleSheets(m_activeAuthorStyleSheets, newCollection.activeAuthorStyleSheets(), addedSheets);
     } else {
         StyleResolverUpdateType updateType = compareStyleSheets(newCollection.activeAuthorStyleSheets(), m_activeAuthorStyleSheets, addedSheets);
         if (updateType != Additive) {
             change.styleResolverUpdateType = updateType;
         } else {
-            if (styleSheetContentsHasFontFaceRule(addedSheets)) {
-                change.styleResolverUpdateType = ResetStyleResolverAndFontSelector;
+            change.styleResolverUpdateType = Reset;
+            // If @font-face is removed, needs full style recalc.
+            if (findFontFaceRulesFromStyleSheetContents(addedSheets, change.fontFaceRulesToRemove))
                 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;
         }
     }
 
     // FIXME: If styleResolverUpdateType is Reconstruct, we should return early here since
     // we need to recalc the whole document. It's wrong to use StyleInvalidationAnalysis since
     // it only looks at the addedSheets.
 
     // No point in doing the analysis work if we're just going to recalc the whole document anyways.
     // This needs to be done after the compareStyleSheets calls above to ensure we don't throw away
     // the StyleResolver if we don't need to.
@@ skipping 42 matching lines @@
     }
     return false;
 }
 
 void StyleSheetCollection::updateUsesRemUnits()
 {
     m_usesRemUnits = styleSheetsUseRemUnits(m_activeAuthorStyleSheets);
 }
 
 }