Remove InProcessBrowserTest::SetUpOnMainThread() calls.

chrome/browser/extensions/api/downloads/downloads_api_browsertest.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.
 
 // Disable everything on windows only. http://crbug.com/306144
 #ifndef OS_WIN
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 298 matching lines @@
   }
 
   Browser* current_browser() { return current_browser_; }
 
   // InProcessBrowserTest
   void SetUpOnMainThread() override {
     ExtensionApiTest::SetUpOnMainThread();
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         base::BindOnce(&chrome_browser_net::SetUrlRequestMocksEnabled, true));
-    InProcessBrowserTest::SetUpOnMainThread();
     GoOnTheRecord();
     CreateAndSetDownloadsDirectory();
     current_browser()->profile()->GetPrefs()->SetBoolean(
         prefs::kPromptForDownload, false);
     events_listener_.reset(new DownloadsEventsListener());
     // Disable file chooser for current profile.
     DownloadTestFileActivityObserver observer(current_browser()->profile());
     observer.EnableFileChooser(false);
   }
 
@@ skipping 3975 matching lines @@
   EXPECT_EQ(downloads::FILENAME_CONFLICT_ACTION_PROMPT, conflict_action);
   EXPECT_FALSE(warnings.empty());
   EXPECT_EQ(Warning::kDownloadFilenameConflict,
             warnings.begin()->warning_type());
   EXPECT_EQ("incumbent", warnings.begin()->extension_id());
 }
 
 }  // namespace extensions
 
 #endif  // http://crbug.com/306144