Wire up download attribution enable finch experiment

chrome/browser/safe_browsing/safe_browsing_navigation_observer_browsertest.cc

 // Copyright 2016 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/strings/stringprintf.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/safe_browsing/download_protection_service.h"
 #include "chrome/browser/safe_browsing/safe_browsing_navigation_observer.h"
@@ skipping 543 matching lines @@
                            referrer_chain[1]);
   VerifyReferrerChainEntry(initial_url,                       // url
                            ReferrerChainEntry::LANDING_PAGE,  // type
                            test_server_ip,                    // ip_address
                            GURL(),                            // referrer_url
                            GURL(),  // referrer_main_frame_url
                            false,   // is_retargeting
                            referrer_chain[2]);
 }
 
-// https://crbug.com/667784: The test is flaky on Linux.
-#if defined(OS_LINUX)
-#define MAYBE_SingleMetaRefreshRedirectTargetBlank DISABLED_SingleMetaRefreshRedirectTargetBlank
-#else
-#define MAYBE_SingleMetaRefreshRedirectTargetBlank SingleMetaRefreshRedirectTargetBlank
-#endif
 // Click on a link which navigates to a page then redirects to a download using
 // META HTTP-EQUIV="refresh". First navigation happens in target blank.
 IN_PROC_BROWSER_TEST_F(SBNavigationObserverBrowserTest,
-                       MAYBE_SingleMetaRefreshRedirectTargetBlank) {
+                       SingleMetaRefreshRedirectTargetBlank) {
   GURL initial_url = embedded_test_server()->GetURL(kSingleFrameTestURL);
   ClickTestLink("single_meta_refresh_redirect_target_blank", 2, initial_url);
   GURL redirect_url = embedded_test_server()->GetURL(kRedirectURL);
   GURL download_url = embedded_test_server()->GetURL(kDownloadItemURL);
   std::string test_server_ip(embedded_test_server()->host_port_pair().host());
   auto nav_map = navigation_map();
   ASSERT_TRUE(nav_map);
   ASSERT_EQ(std::size_t(3), nav_map->size());
   ASSERT_EQ(2U, nav_map->at(redirect_url).size());
   ASSERT_EQ(1U, nav_map->at(download_url).size());
@@ skipping 913 matching lines @@
           yesterday, embedded_test_server()->host_port_pair().host()));
   ASSERT_EQ(1U, ip_map->at(test_server_host).size());
   ClickTestLink("direct_download", 1, initial_url);
   EXPECT_EQ(1U, ip_map->at(test_server_host).size());
   EXPECT_EQ(embedded_test_server()->host_port_pair().host(),
             ip_map->at(test_server_host).back().ip);
   EXPECT_NE(yesterday, ip_map->at(test_server_host).front().timestamp);
 }
 
 }  // namespace safe_browsing