Make DownloadFileImpl handle multiple byte streams.

content/browser/download/mock_download_file.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 "content/browser/download/mock_download_file.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 using ::testing::_;
 using ::testing::Return;
 
 namespace content {
 namespace {
 
 void SuccessRun(const DownloadFile::InitializeCallback& callback) {
   callback.Run(DOWNLOAD_INTERRUPT_REASON_NONE);
 }
 
 }  // namespace
 
 MockDownloadFile::MockDownloadFile() {
   // This is here because |Initialize()| is normally called right after
   // construction.
   ON_CALL(*this, Initialize(_))
       .WillByDefault(::testing::Invoke(SuccessRun));
 }
 
 MockDownloadFile::~MockDownloadFile() {
 }
 
+void MockDownloadFile::AddByteStream(
+    std::unique_ptr<ByteStreamReader> stream_reader,
+    int64_t offset) {
+  // Gmock currently can't mock method that takes move-only parameters,
+  // delegate the EXPECT_CALL count to |DoAddByteStream|.
+  DoAddByteStream(stream_reader.get(), offset);
+}
+
 }  // namespace content