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

chrome/common/spellcheck_common.cc

Index: chrome/common/spellcheck_common.cc
diff --git a/chrome/common/spellcheck_common.cc b/chrome/common/spellcheck_common.cc
index a69249aff91444333a2de8e0c29f34938f40a240..25d26d19d214e7e39f670c290ce89c0d90ffcd82 100644
--- a/chrome/common/spellcheck_common.cc
+++ b/chrome/common/spellcheck_common.cc
@@ -4,8 +4,13 @@
 
 #include "chrome/common/spellcheck_common.h"
 
+#include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.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"
 
 namespace chrome {
@@ -178,5 +183,29 @@ void GetISOLanguageCountryCodeFromLocale(const std::string& locale,
   *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));
+  }
+
+  auto empty_strings_begin =
+      std::partition(dictionary_languages.begin(), dictionary_languages.end(),
+                     [](const std::string& language) {
+        DCHECK(!language.empty());
+        return language.length() > 0;
+      });
+  dictionary_languages.erase(empty_strings_begin, dictionary_languages.end());
+
+  return dictionary_languages;
+}
+
 }  // namespace spellcheck_common
 }  // namespace chrome