Reset fontselector() when removing stylesheets and left stylesheets still have @font-face rules.

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 106 matching lines @@
     if (m_hadActiveLoadingStylesheet && !hasActiveLoadingStylesheet) {
         m_hadActiveLoadingStylesheet = false;
         return true;
     }
     m_hadActiveLoadingStylesheet = hasActiveLoadingStylesheet;
     return false;
 }
 
 static bool styleSheetContentsHasFontFaceRule(Vector<StyleSheetContents*> sheets)
 {
-    for (unsigned i =  0; i < sheets.size(); ++i) {
+    for (unsigned i = 0; i < sheets.size(); ++i) {
         ASSERT(sheets[i]);
         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 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()) {
         change.styleResolverUpdateType = compareStyleSheets(oldStyleSheets, newStyleSheets, addedSheets);
     } else {
         StyleResolverUpdateType updateType = compareStyleSheets(newStyleSheets, oldStyleSheets, addedSheets);
         if (updateType != Additive) {
             change.styleResolverUpdateType = updateType;
         } else {
             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.

[ojan, 2013/11/21 00:57:48]

I'm hoping that once this is done we can get rid of the Reset codepath entirely
and just do Reconstruct instead in those cases (we'd still keep Additive).
Recreating the StyleResolver should be very inexpensive if we're not recreating
the RuleSets.

[tasak, 2013/11/22 05:16:25]

Yeah, I think, this patch is a temporary one.
I see.

+            // So we can remove "styleSheetContentsHasFontFaceRule(newSheets)".
+            if (cssStyleSheetHasFontFaceRule(newStyleSheets))
+                change.styleResolverUpdateType = ResetStyleResolverAndFontSelector;
             change.styleResolverUpdateType = Reset;

[ojan, 2013/11/22 01:08:54]

Hmmm...not lgtm actually. Now that I look more closely at the patch, this line
will always override the work from the new code above.

[tasak, 2013/11/22 05:16:25]

Yeah, It's my fault.

I'm now trying to land the fixing patch for this.

         }
     }
 
     // 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);
@@ skipping 26 matching lines @@
     }
     return false;
 }
 
 void StyleSheetCollection::updateUsesRemUnits()
 {
     m_usesRemUnits = styleSheetsUseRemUnits(m_activeAuthorStyleSheets);
 }
 
 }