Remove content::kFontListSequenceToken.

content/common/font_list_fontconfig.cc

 // Copyright 2016 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 "content/common/font_list.h"
 
 #include <memory>
 #include <set>
 #include <string>
 #include <utility>
 
 #include <fontconfig/fontconfig.h>
 
 #include "base/values.h"
 
 namespace content {
 
 std::unique_ptr<FcPattern, decltype(&FcPatternDestroy)> CreateFormatPattern(
     const char* format) {
   std::unique_ptr<FcPattern, decltype(&FcPatternDestroy)> pattern(
       FcPatternCreate(), FcPatternDestroy);
   FcPatternAddBool(pattern.get(), FC_SCALABLE, FcTrue);
   FcPatternAddString(pattern.get(), FC_FONTFORMAT,
                      reinterpret_cast<const FcChar8*>(format));
   return pattern;
 }
 
 std::unique_ptr<base::ListValue> GetFontList_SlowBlocking() {
+  DCHECK(GetFontListTaskRunner()->RunsTasksInCurrentSequence());
+
   std::unique_ptr<base::ListValue> font_list(new base::ListValue);
 
   std::unique_ptr<FcObjectSet, decltype(&FcObjectSetDestroy)> object_set(
       FcObjectSetBuild(FC_FAMILY, NULL), FcObjectSetDestroy);
 
   std::set<std::string> sorted_families;
 
   // See https://www.freetype.org/freetype2/docs/reference/ft2-font_formats.html
   // for the list of possible formats.
   const char* allowed_formats[] = { "TrueType", "CFF" };
@@ skipping 24 matching lines @@
     font_item->AppendString(family);
     font_item->AppendString(family);  // localized name.
     // TODO(yusukes): Support localized family names.
     font_list->Append(std::move(font_item));
   }
 
   return font_list;
 }
 
 }  // namespace content