Clarify desired behavior of FontConfigTypeface::LegacyCreateTypeface.

src/fonts/SkFontMgr_fontconfig.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkFontMgr.h"
 #include "SkFontStyle.h"
 #include "SkFontConfigInterface.h"
@@ skipping 306 matching lines @@
     }
 
     SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const SK_OVERRIDE {
         SkAutoTDelete<SkStreamAsset> stream(SkStream::NewFromFile(path));
         return stream.get() ? this->createFromStream(stream.detach(), ttcIndex) : NULL;
     }
 
     virtual SkTypeface* onLegacyCreateTypeface(const char familyName[],
                                                unsigned styleBits) const SK_OVERRIDE {
         FCLocker lock;
-        return FontConfigTypeface::LegacyCreateTypeface(NULL, familyName,
-                                                  (SkTypeface::Style)styleBits);
+        return FontConfigTypeface::LegacyCreateTypeface(familyName, (SkTypeface::Style)styleBits);
     }
 };
 
 SkFontMgr* SkFontMgr::Factory() {
     SkFontConfigInterface* fci = RefFCI();
     return fci ? SkNEW_ARGS(SkFontMgr_fontconfig, (fci)) : NULL;
 }