Use unicode-range to prevent unnecessary @font-face donwnloads

Source/core/platform/graphics/FontFallbackList.h

Index: Source/core/platform/graphics/FontFallbackList.h
diff --git a/Source/core/platform/graphics/FontFallbackList.h b/Source/core/platform/graphics/FontFallbackList.h
index edf8dcbe4ab386c223bb9139139dd45d54afc599..a952158d6dfee794e7d876323a91d4ea9d76ef28 100644
--- a/Source/core/platform/graphics/FontFallbackList.h
+++ b/Source/core/platform/graphics/FontFallbackList.h
@@ -73,7 +73,7 @@ public:
     bool isFixedPitch(const Font* f) const { if (m_pitch == UnknownPitch) determinePitch(f); return m_pitch == FixedPitch; };
     void determinePitch(const Font*) const;
 
-    bool loadingCustomFonts() const { return m_loadingCustomFonts; }
+    bool loadingCustomFonts() const;
 
     FontSelector* fontSelector() const { return m_fontSelector.get(); }
     // FIXME: It should be possible to combine fontSelectorVersion and generation.
@@ -88,8 +88,11 @@ private:
     const SimpleFontData* primarySimpleFontData(const Font* f)
     {
         ASSERT(isMainThread());
-        if (!m_cachedPrimarySimpleFontData)
+        if (!m_cachedPrimarySimpleFontData) {
             m_cachedPrimarySimpleFontData = primaryFontData(f)->fontDataForCharacter(' ');
+            if (m_cachedPrimarySimpleFontData)
+                m_cachedPrimarySimpleFontData->beginLoadIfNeeded();
+        }
         return m_cachedPrimarySimpleFontData;
     }