[CRD iOS] Implementing save to keychain and user defaults for login info. Refactor remoting service.

remoting/client/ios/facade/host_list_fetcher.cc

Index: remoting/client/ios/facade/host_list_fetcher.cc
diff --git a/remoting/client/ios/facade/host_list_fetcher.cc b/remoting/client/ios/facade/host_list_fetcher.cc
index 6c1bb008acd2141598cb0b0b9dd6f49608e6292f..e7c4f38ac3c2047dc1f2f1137f3a84d2fe655c4c 100644
--- a/remoting/client/ios/facade/host_list_fetcher.cc
+++ b/remoting/client/ios/facade/host_list_fetcher.cc
@@ -29,6 +29,8 @@ HostListFetcher::~HostListFetcher() {}
 // that. For the moment it will work to make progress in the app.
 void HostListFetcher::RetrieveHostlist(const std::string& access_token,
                                        const HostlistCallback& callback) {
+  // TODO(nicholss): There is a bug here if two host list fetches are happening
+  // at the same time there will be a dcheck thrown. Fix this for release.
   DCHECK(!access_token.empty());
   DCHECK(callback);
   DCHECK(!hostlist_callback_);