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

ios/chrome/browser/voice/voice_search_url_rewriter.mm

 // 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.
 
 #import "ios/chrome/browser/voice/voice_search_url_rewriter.h"
 
 #import <Foundation/Foundation.h>
 
 #import "base/mac/scoped_nsobject.h"
 #import "base/strings/sys_string_conversions.h"
 #include "components/google/core/browser/google_util.h"
 #include "components/prefs/pref_service.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
-#include "ios/chrome/browser/pref_names.h"
 #include "ios/chrome/browser/voice/speech_input_locale_config.h"
+#include "ios/public/provider/chrome/browser/voice/voice_search_prefs.h"
 #include "net/base/url_util.h"
 #include "url/gurl.h"
 
 bool VoiceSearchURLRewriter(GURL* url, web::BrowserState* browser_state) {
   if (!google_util::IsGoogleSearchUrl(*url))
     return false;
 
   ios::ChromeBrowserState* chrome_browser_state =
       ios::ChromeBrowserState::FromBrowserState(browser_state);
   std::string language =
@@ skipping 19 matching lines @@
       net::AppendOrReplaceQueryParameter(rewritten_url, "hl", language);
   rewritten_url =
       net::AppendQueryParameter(rewritten_url, "spknlang", language);
   rewritten_url = net::AppendQueryParameter(rewritten_url, "inm", "vs");
   rewritten_url = net::AppendQueryParameter(rewritten_url, "vse", "1");
   *url = rewritten_url;
 
   // Return false so other URLRewriters can update the url if necessary.
   return false;
 }