Fix crashes in DownloadRequestLimiter when extension popups/bubbles initiate downloads automatically

chrome/browser/download/download_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.
 
 #include <sstream>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
@@ skipping 943 matching lines @@
   // navigate directly to the file we don't want to download because cross-site
   // navigations reset the TabDownloadState.
   FilePath same_site_path(FILE_PATH_LITERAL("download_script.html"));
   GURL same_site_url(URLRequestMockHTTPJob::GetMockUrl(same_site_path));
   ui_test_utils::NavigateToURL(browser(), same_site_url);
 
   // Make sure the initial navigation didn't trigger a download.
   EXPECT_TRUE(EnsureNoPendingDownloads());
 
   // Disable downloads for the tab.
-  content::NavigationController* controller =
-      &browser()->GetSelectedWebContents()->GetController();
+  WebContents* web_contents = browser()->GetSelectedWebContents();
   DownloadRequestLimiter::TabDownloadState* tab_download_state =
       g_browser_process->download_request_limiter()->GetDownloadState(
-          controller,
-          controller,
-          true);
+          web_contents, web_contents, true);
   ASSERT_TRUE(tab_download_state);
   tab_download_state->set_download_status(
       DownloadRequestLimiter::DOWNLOADS_NOT_ALLOWED);
 
   // Try to start the download via Javascript and wait for the corresponding
   // load stop event.
   TestNavigationObserver observer(
-      content::Source<content::NavigationController>(controller),
+      content::Source<content::NavigationController>(
+          &web_contents->GetController()),
       NULL,
       1);
   bool download_assempted;
   ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
       browser()->GetSelectedWebContents()->GetRenderViewHost(),
       L"",
       L"window.domAutomationController.send(startDownload());",
       &download_assempted));
   ASSERT_TRUE(download_assempted);
   observer.WaitForObservation(
@@ skipping 1468 matching lines @@
   GetDownloads(browser(), &download_items);
   ASSERT_EQ(1u, download_items.size());
   ASSERT_EQ(test_server()->GetURL("echoheader?Referer"),
             download_items[0]->GetOriginalUrl());
 
   // Check that the file contains the expected referrer.
   FilePath file(download_items[0]->GetFullPath());
   std::string expected_contents = test_server()->GetURL("").spec();
   ASSERT_TRUE(VerifyFile(file, expected_contents, expected_contents.length()));
 }