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

Source/core/dom/StyleSheetCollection.cpp

Index: Source/core/dom/StyleSheetCollection.cpp
diff --git a/Source/core/dom/StyleSheetCollection.cpp b/Source/core/dom/StyleSheetCollection.cpp
index 90f86fc64ad63135746b58fdb5b69201cebc79b0..6ec0a47c89a66122cd018fb0d53c162d0e24adff 100644
--- a/Source/core/dom/StyleSheetCollection.cpp
+++ b/Source/core/dom/StyleSheetCollection.cpp
@@ -124,7 +124,7 @@ bool StyleSheetCollection::activeLoadingStyleSheetLoaded(const Vector<RefPtr<CSS
 
 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;
@@ -132,6 +132,16 @@ static bool styleSheetContentsHasFontFaceRule(Vector<StyleSheetContents*> sheets
     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))
@@ -155,6 +165,12 @@ void StyleSheetCollection::analyzeStyleSheetChange(StyleResolverUpdateMode updat
                 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.

         }
     }