Introduce ParallelDownloadJob.

content/test/BUILD.gn

 # Copyright 2014 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("//build/config/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
@@ skipping 13 matching lines @@
 
   # See comment at the top of //content/BUILD.gn for why this is disabled in
   # component builds.
   if (is_component_build) {
     check_includes = false
   }
 
   sources = [
     "../browser/download/mock_download_file.cc",
     "../browser/download/mock_download_file.h",
+    "../browser/download/mock_download_item_impl.cc",
+    "../browser/download/mock_download_item_impl.h",
     "../browser/download/mock_download_job.cc",
     "../browser/download/mock_download_job.h",
     "../browser/media/session/mock_media_session_observer.cc",
     "../browser/media/session/mock_media_session_observer.h",
     "../browser/service_worker/embedded_worker_test_helper.cc",
     "../browser/service_worker/embedded_worker_test_helper.h",
     "../browser/service_worker/service_worker_test_utils.cc",
     "../public/test/async_file_test_helper.cc",
     "../public/test/async_file_test_helper.h",
     "../public/test/background_sync_test_util.cc",
@@ skipping 1000 matching lines @@
     "../browser/dom_storage/dom_storage_database_unittest.cc",
     "../browser/dom_storage/local_storage_context_mojo_unittest.cc",
     "../browser/dom_storage/session_storage_database_unittest.cc",
     "../browser/download/base_file_unittest.cc",
     "../browser/download/base_file_win_unittest.cc",
     "../browser/download/download_file_unittest.cc",
     "../browser/download/download_item_impl_unittest.cc",
     "../browser/download/download_job_unittest.cc",
     "../browser/download/download_manager_impl_unittest.cc",
     "../browser/download/download_request_core_unittest.cc",
+    "../browser/download/parallel_download_job_unittest.cc",
     "../browser/download/rate_estimator_unittest.cc",
     "../browser/download/save_package_unittest.cc",
     "../browser/fileapi/copy_or_move_file_validator_unittest.cc",
     "../browser/fileapi/copy_or_move_operation_delegate_unittest.cc",
     "../browser/fileapi/dragged_file_util_unittest.cc",
     "../browser/fileapi/external_mount_points_unittest.cc",
     "../browser/fileapi/file_system_context_unittest.cc",
     "../browser/fileapi/file_system_dir_url_request_job_unittest.cc",
     "../browser/fileapi/file_system_file_stream_reader_unittest.cc",
     "../browser/fileapi/file_system_operation_impl_unittest.cc",
@@ skipping 757 matching lines @@
   if (is_android) {
     deps += [ "//testing/android/native_test:native_test_native_code" ]
   }
 }
 
 group("fuzzers") {
   deps = [
     "//content/test/fuzzer",
   ]
 }