[ios] Adds a VoiceSearchController interface to the provider layer.

ios/chrome/browser/voice/voice_search_prefs_registration.cc

Index: ios/chrome/browser/voice/voice_search_prefs_registration.cc
diff --git a/ios/chrome/browser/voice/voice_search_prefs_registration.cc b/ios/chrome/browser/voice/voice_search_prefs_registration.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9b4f07089abe7c1d530f157274a6d56228d7180c
--- /dev/null
+++ b/ios/chrome/browser/voice/voice_search_prefs_registration.cc
@@ -0,0 +1,16 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ios/chrome/browser/voice/voice_search_prefs_registration.h"
+
+#include "components/pref_registry/pref_registry_syncable.h"
+#include "components/prefs/pref_service.h"
+#include "ios/public/provider/chrome/browser/voice/voice_search_prefs.h"
+
+void RegisterVoiceSearchBrowserStatePrefs(
+    user_prefs::PrefRegistrySyncable* registry) {
+  registry->RegisterStringPref(prefs::kVoiceSearchLocale, std::string(),
+                               user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);
+  registry->RegisterBooleanPref(prefs::kVoiceSearchTTS, true);
+}