Fix hyphenation for lang="de" and other fallback on Android

content/browser/hyphenation/hyphenation_impl.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/browser/hyphenation/hyphenation_impl.h"
 
 #include <algorithm>
 #include <map>
 #include <utility>
 
 #include "base/files/file.h"
 #include "base/files/file_path.h"
+#include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "mojo/public/cpp/system/platform_handle.h"
 
 namespace {
 
 using DictionaryFileMap = std::unordered_map<std::string, base::File>;
 
 static bool IsValidLocale(const std::string& locale) {
-  return std::all_of(locale.cbegin(), locale.cend(),
-                     [](const char ch) { return isalpha(ch) || ch == '-'; });
+  return std::all_of(locale.cbegin(), locale.cend(), [](const char ch) {
+    return base::IsAsciiAlpha(ch) || base::IsAsciiDigit(ch) || ch == '-';
+  });
 }
 
 static base::File& GetDictionaryFile(const std::string& locale) {
   // Keep Files open in the cache for subsequent calls.
   CR_DEFINE_STATIC_LOCAL(DictionaryFileMap, cache, ());
 
   const auto& it = cache.find(locale);
   if (it != cache.end())
     return it->second;
   const auto& inserted = cache.insert(std::make_pair(locale, base::File()));
@@ skipping 30 matching lines @@
   mojo::ScopedHandle handle;
   if (IsValidLocale(locale)) {
     base::File& file = GetDictionaryFile(locale);
     if (file.IsValid())
       handle = mojo::WrapPlatformFile(file.Duplicate().TakePlatformFile());
   }
   callback.Run(std::move(handle));
 }
 
 }  // namespace hyphenation