Allow the default generic font family settings to find the first available font

chrome/browser/ui/webui/options/font_settings_utils.cc

Index: chrome/browser/ui/webui/options/font_settings_utils.cc
diff --git a/chrome/browser/ui/webui/options/font_settings_utils.cc b/chrome/browser/ui/webui/options/font_settings_utils.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ca2465958767faeaaa0dd5cda1cb1ae4721bee87
--- /dev/null
+++ b/chrome/browser/ui/webui/options/font_settings_utils.cc
@@ -0,0 +1,53 @@
+// Copyright (c) 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 "chrome/browser/ui/webui/options/font_settings_utils.h"
+
+#include "base/strings/string_split.h"
+#include "third_party/skia/include/core/SkTypeface.h"
+#include "third_party/skia/include/ports/SkFontMgr.h"
+
+namespace options {
+
+bool IsFontFamilyAvailable(const std::string& family, SkFontMgr* fontManager) {

[msw, 2016/10/27 00:04:18]

If these functions are file-local, they should go in an anon namespace.

[kojii, 2016/10/27 04:50:56]

Done.

+#if defined(OS_LINUX)
+  sk_sp<SkTypeface> typeface(
+      fontManager->legacyCreateTypeface(family.c_str(), SkFontStyle()));
+  return typeface;
+#else
+  sk_sp<SkFontStyleSet> set(fontManager->matchFamily(family.c_str()));
+  return set && set->count();
+#endif
+}
+
+// Returns the first available font. If there is no available font, returns the

[msw, 2016/10/27 00:04:18]

Ditto nit: say 'font name' or 'font family'.

[kojii, 2016/10/27 04:50:56]

Done.

+// first font. Empty entries are ignored.
+std::string FirstAvailableOrFirst(const std::string& font_name_list) {
+  std::vector<std::string> families = base::SplitString(
+      font_name_list, ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
+  if (families.empty())
+    return std::string();
+  sk_sp<SkFontMgr> fm(SkFontMgr::RefDefault());
+  for (auto& family : families) {

[msw, 2016/10/27 00:04:18]

nit: 'const auto&'

[kojii, 2016/10/27 04:50:56]

Done.

+    if (IsFontFamilyAvailable(family, fm.get()))
+      return family;
+  }
+  return families[0];
+}
+
+std::string FontSettingsUtilities::ResolveFontList(
+    const std::string& font_name_or_list) {
+  if (!font_name_or_list.empty() && font_name_or_list[0] == ',')
+    return FirstAvailableOrFirst(font_name_or_list);
+  return font_name_or_list;
+}
+
+#if !defined(OS_WIN)
+std::string FontSettingsUtilities::MaybeGetLocalizedFontName(
+    const std::string& font_name_or_list) {
+  return ResolveFontList(font_name_or_list);
+}
+#endif
+
+}  // namespace options