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

chrome/browser/spellchecker/spellcheck_service.cc

Index: chrome/browser/spellchecker/spellcheck_service.cc
diff --git a/chrome/browser/spellchecker/spellcheck_service.cc b/chrome/browser/spellchecker/spellcheck_service.cc
index f40924e8c18e3ff48c2c981a1514e2ff5b7ce827..d07b86a3e5d46c0ccb33ef0acd3d767dc6e821aa 100644
--- a/chrome/browser/spellchecker/spellcheck_service.cc
+++ b/chrome/browser/spellchecker/spellcheck_service.cc
@@ -4,6 +4,9 @@
 
 #include "chrome/browser/spellchecker/spellcheck_service.h"
 
+#include <algorithm>
+
+#include "base/command_line.h"
 #include "base/prefs/pref_member.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/string_split.h"
@@ -13,6 +16,7 @@
 #include "chrome/browser/spellchecker/spellcheck_hunspell_dictionary.h"
 #include "chrome/browser/spellchecker/spellcheck_platform_mac.h"
 #include "chrome/browser/spellchecker/spelling_service_client.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/spellcheck_messages.h"
 #include "components/user_prefs/user_prefs.h"
@@ -75,19 +79,34 @@ SpellcheckService::~SpellcheckService() {
 }
 
 // static
-int SpellcheckService::GetSpellCheckLanguages(
-    content::BrowserContext* context,
-    std::vector<std::string>* languages) {
+std::set<int> SpellcheckService::GetSpellCheckLanguages(
+      content::BrowserContext* context,
+      std::vector<std::string>* languages) {
   PrefService* prefs = user_prefs::UserPrefs::Get(context);
-  StringPrefMember accept_languages_pref;
-  StringPrefMember dictionary_language_pref;
-  accept_languages_pref.Init(prefs::kAcceptLanguages, prefs);
-  dictionary_language_pref.Init(prefs::kSpellCheckDictionary, prefs);
-  std::string dictionary_language = dictionary_language_pref.GetValue();
+  std::vector<std::string> dictionary_languages;
+
+  const base::CommandLine* command_line =
+      base::CommandLine::ForCurrentProcess();
+
+  StringPrefMember dictionary_languages_pref;
+  if (command_line->HasSwitch(switches::kEnableMultilingualSpellChecker)) {
+    dictionary_languages_pref.Init(prefs::kSpellCheckDictionaries, prefs);
+    base::SplitString(dictionary_languages_pref.GetValue(),
+                      chrome::spellcheck_common::kDictionaryLanguagesSeparator,
+                      &dictionary_languages);
+  } else {
+    dictionary_languages_pref.Init(prefs::kSpellCheckDictionary, prefs);
+    dictionary_languages.push_back(dictionary_languages_pref.GetValue());
+  }
+
+  auto partition_point = std::partition(
+      dictionary_languages.begin(), dictionary_languages.end(),
+      [](const std::string& language) { return language.length() > 0; });
+  dictionary_languages.erase(partition_point, dictionary_languages.end());

[please use gerrit instead, 2015/02/26 21:30:19]

Instead of repeating this code, perhaps we can put it in spellcheck_common?

std::vector<std::string> GetDictionaryLanguagesPref();

Also, please place a "DCHECK_LT(0, language.length());" inside of the lambda
function. This will help you catch any code that mistakenly writes empty entries
into your preference string. (DCHECKs trigger only in debug builds.)

[Dan Beam, 2015/02/26 22:04:32]

size_t < 0?! mind == blown. i think rouslan@ meant GT (greater than, >), but the
easiest would be:

  DCHECK(!language.empty());

[Dan Beam, 2015/02/26 22:30:23]

oh, I guess the operand order is right in rouslan@'s command, but I think
!empty() is easier to grok

[Klemen Forstnerič, 2015/02/27 15:43:44]

I think so too, DCHECK(!language.empty()) is more readable. Done.

[Klemen Forstnerič, 2015/02/27 15:43:44]

Good idea. Done.

 
-  // Now scan through the list of accept languages, and find possible mappings
-  // from this list to the existing list of spell check languages.
   std::vector<std::string> accept_languages;
+  StringPrefMember accept_languages_pref;
+  accept_languages_pref.Init(prefs::kAcceptLanguages, prefs);
 
 #if defined(OS_MACOSX)
   if (spellcheck_mac::SpellCheckerAvailable())
@@ -98,23 +117,22 @@ int SpellcheckService::GetSpellCheckLanguages(
   base::SplitString(accept_languages_pref.GetValue(), ',', &accept_languages);
 #endif  // !OS_MACOSX
 
-  GetSpellCheckLanguagesFromAcceptLanguages(
-      accept_languages, dictionary_language, languages);
+  *languages = dictionary_languages;
+  GetSpellCheckLanguagesFromAcceptLanguages(accept_languages, languages);
 
-  for (size_t i = 0; i < languages->size(); ++i) {
-    if ((*languages)[i] == dictionary_language)
-      return i;
-  }
-  return -1;
+  // |languages| vector begins with the entries from |dictionary_languages|,
+  // therefore these indices are correct.
+  std::set<int> selected_language_indices;
+  for (size_t i = 0; i < dictionary_languages.size(); ++i)
+    selected_language_indices.insert(i);
+
+  return selected_language_indices;
 }
 
 // static
 void SpellcheckService::GetSpellCheckLanguagesFromAcceptLanguages(
     const std::vector<std::string>& accept_languages,
-    const std::string& dictionary_language,
     std::vector<std::string>* languages) {
-  // The current dictionary language should be there.
-  languages->push_back(dictionary_language);
 
   for (std::vector<std::string>::const_iterator i = accept_languages.begin();
        i != accept_languages.end(); ++i) {