Eliminate usage of InterfacePtr::WaitForIncomingResponse.

components/filesystem/files_test_base.cc

 // Copyright 2015 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 "components/filesystem/files_test_base.h"
 
 #include <utility>
 
 #include "components/filesystem/public/interfaces/directory.mojom.h"
 #include "components/filesystem/public/interfaces/types.mojom.h"
 #include "services/shell/public/cpp/connector.h"
 
 namespace filesystem {
 
 FilesTestBase::FilesTestBase() : ShellTest("exe:filesystem_service_unittests") {
 }
 
 FilesTestBase::~FilesTestBase() {
 }
 
 void FilesTestBase::SetUp() {
   ShellTest::SetUp();
   connector()->ConnectToInterface("mojo:filesystem", &files_);
 }
 
 void FilesTestBase::GetTemporaryRoot(mojom::DirectoryPtr* directory) {
   mojom::FileError error = mojom::FileError::FAILED;
-  files()->OpenTempDirectory(GetProxy(directory), Capture(&error));
-  ASSERT_TRUE(files().WaitForIncomingResponse());
+  bool handled = files()->OpenTempDirectory(GetProxy(directory), &error);
+  ASSERT_TRUE(handled);
   ASSERT_EQ(mojom::FileError::OK, error);
 }
 
 }  // namespace filesystem