Reduced the callers to the non-const version of CSSValueList::item()

third_party/WebKit/Source/core/css/CSSFontFaceSrcValue.h

 /*
  * Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 43 matching lines @@
 
     void setFormat(const String& format) { m_format = format; }
     void setReferrer(const Referrer& referrer) { m_referrer = referrer; }
 
     bool isSupportedFormat() const;
 
     String customCSSText() const;
 
     bool hasFailedOrCanceledSubresources() const;
 
-    FontResource* fetch(Document*);
+    FontResource* fetch(Document*) const;
 
     bool equals(const CSSFontFaceSrcValue&) const;
 
     DEFINE_INLINE_TRACE_AFTER_DISPATCH()
     {
         visitor->trace(m_fetched);
         CSSValue::traceAfterDispatch(visitor);
     }
 
 private:
     CSSFontFaceSrcValue(const String& specifiedResource, const String& absoluteResource, bool local, ContentSecurityPolicyDisposition shouldCheckContentSecurityPolicy)
         : CSSValue(FontFaceSrcClass)
         , m_absoluteResource(absoluteResource)
         , m_specifiedResource(specifiedResource)
         , m_isLocal(local)
         , m_shouldCheckContentSecurityPolicy(shouldCheckContentSecurityPolicy)
     {
     }
 
-    void restoreCachedResourceIfNeeded(Document*);
+    void restoreCachedResourceIfNeeded(Document*) const;
 
     String m_absoluteResource;
     String m_specifiedResource;
     String m_format;
     Referrer m_referrer;
     bool m_isLocal;
     ContentSecurityPolicyDisposition m_shouldCheckContentSecurityPolicy;
 
 
     class FontResourceHelper : public GarbageCollectedFinalized<FontResourceHelper>, public ResourceOwner<FontResource> {
         USING_GARBAGE_COLLECTED_MIXIN(FontResourceHelper);
     public:
         static FontResourceHelper* create(FontResource* resource)
         {
             return new FontResourceHelper(resource);
         }
 
         DEFINE_INLINE_VIRTUAL_TRACE() { ResourceOwner<FontResource>::trace(visitor); }
 
     private:
         FontResourceHelper(FontResource* resource)
         {
             setResource(resource);
         }
 
         String debugName() const override { return "CSSFontFaceSrcValue::FontResourceHelper"; }
     };
-    Member<FontResourceHelper> m_fetched;
+    mutable Member<FontResourceHelper> m_fetched;
 };
 
 DEFINE_CSS_VALUE_TYPE_CASTS(CSSFontFaceSrcValue, isFontFaceSrcValue());
 
 } // namespace blink
 
 #endif