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

chrome/browser/spellchecker/spellcheck_factory.cc

Index: chrome/browser/spellchecker/spellcheck_factory.cc
diff --git a/chrome/browser/spellchecker/spellcheck_factory.cc b/chrome/browser/spellchecker/spellcheck_factory.cc
index 7d7e1df68fa11fd40643e1065c3dc9c7e85e1362..74afcc2f8213f26e6d69fcca2d4a450ef85a6f5a 100644
--- a/chrome/browser/spellchecker/spellcheck_factory.cc
+++ b/chrome/browser/spellchecker/spellcheck_factory.cc
@@ -4,9 +4,11 @@
 
 #include "chrome/browser/spellchecker/spellcheck_factory.h"
 
+#include "base/command_line.h"
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/spellchecker/spellcheck_service.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/grit/locale_settings.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
@@ -68,10 +70,19 @@ KeyedService* SpellcheckServiceFactory::BuildServiceInstanceFor(
 void SpellcheckServiceFactory::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* user_prefs) {
   // TODO(estade): IDS_SPELLCHECK_DICTIONARY should be an ASCII string.
-  user_prefs->RegisterStringPref(
-      prefs::kSpellCheckDictionary,
-      l10n_util::GetStringUTF8(IDS_SPELLCHECK_DICTIONARY),
-      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableMultilingualSpellChecker)) {

[groby-ooo-7-16, 2015/03/03 17:54:34]

How is preference migration handled? (I.e. what happens if I enable/disable
multiple spellchecks)

+    user_prefs->RegisterStringPref(
+        prefs::kSpellCheckDictionaries,
+        l10n_util::GetStringUTF8(IDS_SPELLCHECK_DICTIONARY),
+        user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+  } else {
+    user_prefs->RegisterStringPref(
+        prefs::kSpellCheckDictionary,
+        l10n_util::GetStringUTF8(IDS_SPELLCHECK_DICTIONARY),
+        user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);

[Dan Beam, 2015/03/02 22:40:08]

do these preferences need to be migrated?

[groby-ooo-7-16, 2015/03/03 17:54:34]

Heh. That was off-screen when I asked :)

+  }
+
   user_prefs->RegisterBooleanPref(
       prefs::kSpellCheckUseSpellingService,
       false,