Remove the (broken and unneeded) 'force_update' option from ServiceWatcher::DiscoverNewDevices.

chrome/browser/local_discovery/service_discovery_client_mac.mm

 // Copyright 2013 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 "chrome/browser/local_discovery/service_discovery_client_mac.h"
 
 #import <arpa/inet.h>
 #import <Foundation/Foundation.h>
 #import <net/if_dl.h>
 #include <stddef.h>
@@ skipping 253 matching lines @@
 
 ServiceWatcherImplMac::~ServiceWatcherImplMac() {}
 
 void ServiceWatcherImplMac::Start() {
   DCHECK(!started_);
   VLOG(1) << "ServiceWatcherImplMac::Start";
   container_->Start();
   started_ = true;
 }
 
-void ServiceWatcherImplMac::DiscoverNewServices(bool force_update) {
+void ServiceWatcherImplMac::DiscoverNewServices() {
   DCHECK(started_);
   VLOG(1) << "ServiceWatcherImplMac::DiscoverNewServices";
   container_->DiscoverNewServices();
 }
 
 void ServiceWatcherImplMac::SetActivelyRefreshServices(
     bool actively_refresh_services) {
   DCHECK(started_);
   VLOG(1) << "ServiceWatcherImplMac::SetActivelyRefreshServices";
 }
@@ skipping 217 matching lines @@
   container_->OnResolveUpdate(local_discovery::ServiceResolver::STATUS_SUCCESS);
 }
 
 - (void)netService:(NSNetService*)sender
         didNotResolve:(NSDictionary*)errorDict {
   container_->OnResolveUpdate(
       local_discovery::ServiceResolver::STATUS_REQUEST_TIMEOUT);
 }
 
 @end