Automatically trigger installation of high-quality speech synthesis extension.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 1144e7241b0ec572b94a8bdd8a24bc86d4d02287..ecaabe3954d275e362db8b5340f48a9c447fbc06 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -853,6 +853,11 @@ const char kMultiProfileNotificationDismissed[] =
 // in a multiprofile session. See ChromeOsMultiProfileUserBehavior policy
 // for more details of the valid values.
 const char kMultiProfileUserBehavior[] = "settings.multiprofile_user_behavior";
+
+// List of the set of language codes for which high quality local speech
+// synthesis has been enabled.
+const char kHighQualitySpeechSynthesisLanguages[] =
+    "settings.speech_synthesis.high_quality_languages";
 #endif  // defined(OS_CHROMEOS)
 
 // The disabled messages in IPC logging.