Polish the cleaning up url request code for parallel download.

content/browser/download/download_file_unittest.cc

 // Copyright (c) 2012 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 <stddef.h>
 #include <stdint.h>
 
 #include <utility>
 #include <vector>
 
@@ skipping 971 matching lines @@
   VerifySourceStreamsStates(stream_data_1);
   VerifySourceStreamsStates(stream_data_2);
 
   EXPECT_EQ(stream_0_length + stream_1_length + stream_2_length,
             TotalBytesReceived());
 
   download_file_->Cancel();
   DestroyDownloadFile(0, false);
 }
 
-//  Activate and deplete one stream, later add the second stream.
+// Activate and deplete one stream, later add the second stream.
 TEST_F(DownloadFileTest, MutipleStreamsFirstStreamWriteAllData) {
   int64_t stream_0_length = GetBuffersLength(kTestData8, 4);
 
   ASSERT_TRUE(CreateDownloadFile(0, DownloadSaveInfo::kLengthFullContent, true,
                                  DownloadItem::ReceivedSlices()));
 
   PrepareStream(&input_stream_, 0, false, true, kTestData8, 4);
 
   EXPECT_CALL(*(observer_.get()), MockDestinationCompleted(_, _));
 
@@ skipping 13 matching lines @@
   SourceStreamTestData stream_data_0(0, stream_0_length, true);
   SourceStreamTestData stream_data_1(stream_0_length - 1, 0, false);
   VerifySourceStreamsStates(stream_data_0);
   VerifySourceStreamsStates(stream_data_1);
   EXPECT_EQ(stream_0_length, TotalBytesReceived());
 
   DestroyDownloadFile(0);
 }
 
 }  // namespace content