Created a DownloadManager interface, for use in unit tests..

chrome/browser/download/download_browsertest.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/bind.h"
 #include "base/bind_helpers.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/path_service.h"
@@ skipping 149 matching lines @@
 };
 
 // Get History Information.
 class DownloadsHistoryDataCollector {
  public:
   DownloadsHistoryDataCollector(int64 download_db_handle,
                                 DownloadManager* manager)
       : result_valid_(false),
         download_db_handle_(download_db_handle) {
     HistoryService* hs =
-        Profile::FromBrowserContext(manager->browser_context())->
+        Profile::FromBrowserContext(manager->BrowserContext())->
             GetHistoryService(Profile::EXPLICIT_ACCESS);
     DCHECK(hs);
     hs->QueryDownloads(
         &callback_consumer_,
         base::Bind(&DownloadsHistoryDataCollector::OnQueryDownloadsComplete,
                    base::Unretained(this)));
 
     // TODO(rdsmith): Move message loop out of constructor.
     // Cannot complete immediately because the history backend runs on a
     // separate thread, so we can assume that the RunMessageLoop below will
@@ skipping 1494 matching lines @@
   search_results.clear();
 
   manager->SearchDownloads(UTF8ToUTF16("another_file"), &search_results);
   ASSERT_EQ(2u, search_results.size());
   std::sort(search_results.begin(), search_results.end(),
             DownloadItemSorter);
   EXPECT_EQ(2, search_results[0]->db_handle());
   EXPECT_EQ(3, search_results[1]->db_handle());
   search_results.clear();
 }