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 372c106b17652d694856978ff1a64df01cba5322..ec9b043d9a0c361554f8eb24e680820e2fee3aa0 100644
--- a/chrome/common/spellcheck_common.cc
+++ b/chrome/common/spellcheck_common.cc
@@ -4,9 +4,14 @@
 
 #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"
@@ -181,5 +186,34 @@ 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));
+  }
+
+  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