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

Source/core/rendering/RenderText.cpp

Index: Source/core/rendering/RenderText.cpp
diff --git a/Source/core/rendering/RenderText.cpp b/Source/core/rendering/RenderText.cpp
index 8d4b5fd8d8af6a44cf87e2f37fec15ffa6ca7475..1fe720b0f5e1fc52966d2c844cc490b546038cc0 100644
--- a/Source/core/rendering/RenderText.cpp
+++ b/Source/core/rendering/RenderText.cpp
@@ -204,8 +204,11 @@ void RenderText::styleDidChange(StyleDifference diff, const RenderStyle* oldStyl
     if (oldTransform != newStyle->textTransform() || oldSecurity != newStyle->textSecurity())
         transformText();
 
+    // This is an optimization that kicks off font load before layout.
+    // In order to make it fast, we only check if the first character of the
+    // text is included in the unicode ranges of the fonts.
     if (!text().containsOnlyWhitespace())
-        newStyle->font().willUseFontData();
+        newStyle->font().willUseFontData(text().characterStartingAt(0));
 }
 
 void RenderText::removeAndDestroyTextBoxes()