Remove leftover use of deprecated variables

So system_api can be upreved.

BUG=1071262
TEST=unittests

Change-Id: I20eaf9671e9094eb9304eea161af6e530ab3e974
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2237393
Auto-Submit: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Amin Hassani <ahassani@chromium.org>
Cr-Commit-Position: refs/heads/master@{#776604}

chromeos/dbus/dlcservice/dlcservice_client_unittest.cc

@@ -271,8 +271,6 @@ TEST_F(DlcserviceClientTest, PurgeBusyStatusTest) {
 
 TEST_F(DlcserviceClientTest, InstallSuccessTest) {
   responses_.push_back(dbus::Response::CreateEmpty());
-  dbus::MessageWriter writer(responses_.back().get());
-  writer.AppendProtoAsArrayOfBytes(dlcservice::DlcModuleList());
 
   EXPECT_CALL(*mock_proxy_.get(), DoCallMethodWithErrorResponse(_, _, _))
       .WillOnce(

chromeos/dbus/dlcservice/fake_dlcservice_client.h

@@ -45,9 +45,6 @@ class COMPONENT_EXPORT(DLCSERVICE_CLIENT) FakeDlcserviceClient
   void SetGetExistingDlcsError(const std::string& err) {
     get_existing_dlcs_err_ = err;
   }
-  void set_installed_dlcs(const dlcservice::DlcModuleList& dlc_module_list) {
-    dlc_module_list_ = dlc_module_list;
-  }
   void set_dlcs_with_content(
       const dlcservice::DlcsWithContent& dlcs_with_content) {
     dlcs_with_content_ = dlcs_with_content;
@@ -58,7 +55,6 @@ class COMPONENT_EXPORT(DLCSERVICE_CLIENT) FakeDlcserviceClient
   std::string uninstall_err_ = dlcservice::kErrorNone;
   std::string purge_err_ = dlcservice::kErrorNone;
   std::string get_installed_err_ = dlcservice::kErrorNone;
-  dlcservice::DlcModuleList dlc_module_list_;
   std::string get_existing_dlcs_err_ = dlcservice::kErrorNone;
   dlcservice::DlcsWithContent dlcs_with_content_;