Extend FontCache fallback API to support FontFallbackPriority

third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Computer, Inc.
  * Copyright (c) 2006, 2007, 2008, 2009, 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 97 matching lines @@
     // Subpixel text positioning is only supported by the DirectWrite backend (not GDI).
     s_useSubpixelPositioning = s_useDirectWrite;
 
     ASSERT(m_fontManager.get());
 }
 
 // Given the desired base font, this will create a SimpleFontData for a specific
 // font that can be used to render the given range of characters.
 PassRefPtr<SimpleFontData> FontCache::fallbackFontForCharacter(
     const FontDescription& fontDescription, UChar32 character,
-    const SimpleFontData* originalFontData)
+    const SimpleFontData* originalFontData,
+    FontFallbackPriority fallbackPriority)
 {
     // First try the specified font with standard style & weight.
-    if (fontDescription.style() == FontStyleItalic
-        || fontDescription.weight() >= FontWeightBold) {
+    if (fallbackPriority != FontFallbackPriority::EmojiEmoji
+        && (fontDescription.style() == FontStyleItalic
+        || fontDescription.weight() >= FontWeightBold)) {
         RefPtr<SimpleFontData> fontData = fallbackOnStandardFontStyle(
             fontDescription, character);
         if (fontData)
             return fontData;
     }
 
     UScriptCode script;
     const wchar_t* family = getFallbackFamily(character,
         fontDescription.genericFamily(),
         fontDescription.script(),
         fontDescription.locale(),
         &script,
+        fallbackPriority,
         m_fontManager.get());
     FontPlatformData* data = 0;
     if (family) {
         FontFaceCreationParams createByFamily(AtomicString(family, wcslen(family)));
         data = getFontPlatformData(fontDescription, createByFamily);
     }
 
     // Last resort font list : PanUnicode. CJK fonts have a pretty
     // large repertoire. Eventually, we need to scan all the fonts
     // on the system to have a Firefox-like coverage.
@@ skipping 274 matching lines @@
         if (typefacesMatchesFamily(tf.get(), family)) {
             result->setMinSizeForSubpixel(minSizeForSubpixelForFont);
             break;
         }
     }
 
     return result.release();
 }
 
 } // namespace blink