Reland r172943 "Make CSSFontFace::willUseFontData() load fonts with unicode-range"

Source/core/css/CSSFontFace.h

Index: Source/core/css/CSSFontFace.h
diff --git a/Source/core/css/CSSFontFace.h b/Source/core/css/CSSFontFace.h
index 6b5e684fc1eee4207373d72825478279541cdf12..427ba0f3dfbde19c312d5e851d9ba5018d463d0d 100644
--- a/Source/core/css/CSSFontFace.h
+++ b/Source/core/css/CSSFontFace.h
@@ -97,6 +97,7 @@ public:
     class UnicodeRangeSet {
     public:
         explicit UnicodeRangeSet(const Vector<UnicodeRange>&);
+        bool contains(UChar32) const;
         bool intersectsWith(const String&) const;
         bool isEntireRange() const { return m_ranges.isEmpty(); }
         size_t size() const { return m_ranges.size(); }
@@ -106,7 +107,7 @@ public:
     };
 
     FontFace::LoadStatus loadStatus() const { return m_fontFace->loadStatus(); }
-    void willUseFontData(const FontDescription&);
+    bool maybeScheduleFontLoad(const FontDescription&, UChar32);
     void load(const FontDescription&, CSSFontSelector* = 0);
 
     bool hadBlankText() { return isValid() && m_sources.first()->hadBlankText(); }