Split DownloadItem into an ABC, an Impl, and a Mock.

content/browser/download/download_id_unittest.cc

 // Copyright (c) 2011 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/download_id.h"
 
 #include <algorithm>
 #include <map>
 #include <set>
 #include <vector>
 
+#include "base/memory/scoped_ptr.h"
 #include "content/browser/browser_thread_impl.h"
 #include "content/browser/download/mock_download_manager.h"
 #include "content/browser/download/mock_download_manager_delegate.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using content::BrowserThread;
 using content::BrowserThreadImpl;
 
 class DownloadIdTest : public testing::Test {
  public:
@@ skipping 123 matching lines @@
   EXPECT_EQ(kLocalId[2], map[id3]);
   last = map.end();
   EXPECT_FALSE(last == map.find(id1));
   EXPECT_FALSE(last == map.find(id2));
   EXPECT_FALSE(last == map.find(id3));
 
   EXPECT_FALSE(id1 == id2);
   EXPECT_LT(id1, id2);
 }