Add FontCache API for retrieving prioritized fallback fonts

third_party/WebKit/Source/platform/fonts/FontCacheTest.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/fonts/FontCache.h"
 
 #include "platform/fonts/FontDescription.h"
 #include "platform/fonts/SimpleFontData.h"
 #include "platform/testing/TestingPlatformSupport.h"
 #include "public/platform/Platform.h"
@@ skipping 17 matching lines @@
     FontDescription fontDescription;
     fontDescription.setGenericFamily(FontDescription::StandardFamily);
     RefPtr<SimpleFontData> fontData = fontCache->getLastResortFallbackFont(fontDescription, Retain);
     EXPECT_TRUE(fontData);
 
     fontDescription.setGenericFamily(FontDescription::SansSerifFamily);
     fontData = fontCache->getLastResortFallbackFont(fontDescription, Retain);
     EXPECT_TRUE(fontData);
 }
 
+TEST(FontCache, availablePriorityFallbackFonts)
+{
+    FontCache* fontCache = FontCache::fontCache();
+    ASSERT_TRUE(fontCache);
+
+    EmptyPlatform platform;
+
+    FontDescription fontDescription;
+    fontDescription.setGenericFamily(FontDescription::StandardFamily);
+
+    for (FontFallbackPriority fallbackPriority :
+        { FontFallbackPriority::Symbols,
+            FontFallbackPriority::Math,
+            FontFallbackPriority::EmojiText,
+            FontFallbackPriority::EmojiEmoji }) {
+
+        const Vector<AtomicString> availableFallbackPriorityFonts =
+            fontCache->fontListForFallbackPriority(fontDescription,
+            fallbackPriority);
+        EXPECT_GE(availableFallbackPriorityFonts.size(), 1u);
+    }
+}
+
 } // namespace blink