Enable multilingual spellcheck by default.

This patch enables multilingual spellcheck by default with an option to
disable it on demand via field trial.

BUG=5102

Review URL: https://codereview.chromium.org/1389153002

Cr-Commit-Position: refs/heads/master@{#353107}

1 files changed, 19 insertions, 2 deletions

diff --git a/chrome/common/spellcheck_common.cc b/chrome/common/spellcheck_common.cc
index 9aa3a02..cee0883 100644
--- a/chrome/common/spellcheck_common.cc
+++ b/chrome/common/spellcheck_common.cc
@@ -8,6 +8,8 @@
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/metrics/field_trial.h"
+#include "base/strings/string_util.h"
 #include "chrome/common/chrome_switches.h"
 #include "third_party/icu/source/common/unicode/uloc.h"
 #include "third_party/icu/source/common/unicode/urename.h"
@@ -16,6 +18,8 @@
 namespace chrome {
 namespace spellcheck_common {
 
+const char kMultilingualSpellcheckFieldTrial[] = "MultilingualSpellcheck";
+
 struct LanguageRegion {
   const char* language;  // The language.
   const char* language_region;  // language & region, used by dictionaries.
@@ -184,8 +188,21 @@ void GetISOLanguageCountryCodeFromLocale(const std::string& locale,
 }
 
 bool IsMultilingualSpellcheckEnabled() {
-  return base::CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kEnableMultilingualSpellChecker);
+  // TODO(rouslan): Remove field trial and command line flags when M49 is
+  // stable.
+  const std::string& group_name =
+      base::FieldTrialList::FindFullName(kMultilingualSpellcheckFieldTrial);
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableMultilingualSpellChecker)) {
+    return false;
+  }
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableMultilingualSpellChecker)) {
+    return true;
+  }
+  // Enabled by default, but can be disabled in field trial.
+  return !base::StartsWith(group_name, "Disabled",
+                           base::CompareCase::INSENSITIVE_ASCII);
 }
 
 }  // namespace spellcheck_common