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

chrome/browser/download/download_item_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 "base/message_loop.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/browser/download/download_create_info.h"
 #include "content/browser/download/download_id.h"
 #include "content/browser/download/download_id_factory.h"
 #include "content/browser/download/download_item.h"
 #include "content/browser/download/download_status_updater.h"
 #include "content/browser/download/interrupt_reasons.h"
+#include "content/browser/download/mock_download_item.h"
 #include "content/browser/download/mock_download_manager.h"
 #include "content/browser/download/mock_download_manager_delegate.h"
 #include "content/test/test_browser_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using content::BrowserThread;
 
 DownloadId::Domain kValidDownloadItemIdDomain = "valid DownloadId::Domain";
 
 class DownloadItemTest : public testing::Test {
@@ skipping 221 matching lines @@
 TEST_F(DownloadItemTest, NotificationAfterTogglePause) {
   DownloadItem* item = CreateDownloadItem(DownloadItem::IN_PROGRESS);
   MockObserver observer(item);
 
   item->TogglePause();
   ASSERT_TRUE(observer.CheckUpdated());
 
   item->TogglePause();
   ASSERT_TRUE(observer.CheckUpdated());
 }
+
+TEST(MockDownloadItem, Compiles) {
+  MockDownloadItem mock_item;
+}