Render Unicode control characters

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

 // Copyright 2015 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/FontFallbackIterator.h"
 
 #include "platform/Logging.h"
 #include "platform/fonts/FontCache.h"
 #include "platform/fonts/FontDescription.h"
 #include "platform/fonts/FontFallbackList.h"
@@ skipping 164 matching lines @@
 {
     return FontCache::fontCache()->fallbackFontForCharacter(
         m_fontDescription,
         hint,
         m_fontFallbackList->primarySimpleFontData(m_fontDescription),
         m_fontFallbackPriority);
 }
 
 const PassRefPtr<SimpleFontData> FontFallbackIterator::uniqueSystemFontForHint(UChar32 hint)
 {
-    FontCache* fontCache = FontCache::fontCache();
-
     // When we're asked for a fallback for the same characters again, we give up
     // because the shaper must have previously tried shaping with the font
     // already.
-    if (m_previouslyAskedForHint.contains(hint))
+    if (!hint || m_previouslyAskedForHint.contains(hint))
         return nullptr;
 
+    FontCache* fontCache = FontCache::fontCache();
     m_previouslyAskedForHint.add(hint);
     return fontCache->fallbackFontForCharacter(m_fontDescription, hint, m_fontFallbackList->primarySimpleFontData(m_fontDescription));
 }
 
 } // namespace blink