Enables the user to select multiple languages for spellchecking (UI)

chrome/common/spellcheck_common.cc

 // Copyright (c) 2012 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/common/spellcheck_common.h"
 
+#include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/prefs/pref_service.h"
+#include "base/strings/string_split.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/common/pref_names.h"
 #include "third_party/icu/source/common/unicode/uloc.h"
 #include "third_party/icu/source/common/unicode/urename.h"
 #include "third_party/icu/source/common/unicode/utypes.h"
 
 namespace chrome {
 namespace spellcheck_common {
 
 struct LanguageRegion {
   const char* language;  // The language.
   const char* language_region;  // language & region, used by dictionaries.
@@ skipping 154 matching lines @@
     char id[ULOC_LANG_CAPACITY + ULOC_SCRIPT_CAPACITY + ULOC_COUNTRY_CAPACITY];
     uloc_addLikelySubtags(locale.c_str(), id, arraysize(id), &error);
     error = U_ZERO_ERROR;
     uloc_getLanguage(id, language, arraysize(language), &error);
     country = uloc_getISO3Country(id);
   }
   *language_code = std::string(language);
   *country_code = std::string(country);
 }
 
+std::vector<std::string> GetDictionaryLanguagesPref(PrefService* prefs) {
+  const base::CommandLine* command_line =
+      base::CommandLine::ForCurrentProcess();
+
+  std::vector<std::string> dictionary_languages;
+  if (command_line->HasSwitch(switches::kEnableMultilingualSpellChecker)) {
+    base::SplitString(prefs->GetString(prefs::kSpellCheckDictionaries),
+                      kDictionaryLanguagesSeparator, &dictionary_languages);
+  } else {
+    dictionary_languages.push_back(
+        prefs->GetString(prefs::kSpellCheckDictionary));
+  }
+
+  dictionary_languages.erase(
+      std::partition(dictionary_languages.begin(), dictionary_languages.end(),
+                     [](const std::string& language) {
+                       DCHECK(!language.empty());

[please use gerrit instead, 2015/06/06 01:42:13]

Be sure to remove this DCHECK() when you submit this patch into the commit
queue.

DCHECK(!language.empty());  // TODO(juliusa): Remove before commit.

We either DCHECK(condition) or handle the condition manually, but not both. In
this case, the DHCECK() is useful during development to make sure that you're
not accidentally adding empty strings to the list. After development is
complete, handling empty strings is necessary for disk corruption. (I did not
see any validity guarantees in prefs API.


See
https://www.chromium.org/developers/coding-style#TOC-CHECK-DCHECK-and-NOTREAC...

[Julius, 2015/06/12 20:10:15]

Done.

+                       return language.length() > 0;
+                     }),
+      dictionary_languages.end());
+
+  return dictionary_languages;
+}
+
+bool MultilingualSpellcheckIsEnabled() {
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableMultilingualSpellChecker);
+}
+
 }  // namespace spellcheck_common
 }  // namespace chrome