Fix some more tests that were writing to the user's home directory.

The tests affected are:
    PolicyTest.ExtensionInstallSources
    PrefsFunctionalTest.TestDownloadDirPref
    WebNavigationApiTest.Download

BUG=372017
R=bauerb@chromium.org
TBR=jam, joaodasilva

Review URL: https://codereview.chromium.org/273233004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269639 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/extensions/api/web_navigation/web_navigation_apitest.cc

@@ -5,6 +5,7 @@
 #include <list>
 #include <set>
 
+#include "base/files/scoped_temp_dir.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/strings/string_util.h"
@@ -17,6 +18,7 @@
 #include "chrome/browser/chrome_content_browser_client.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/download/download_browsertest.h"
+#include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/extensions/api/web_navigation/web_navigation_api.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ -321,6 +323,12 @@ IN_PROC_BROWSER_TEST_F(WebNavigationApiTest, ServerRedirect) {
 }
 
 IN_PROC_BROWSER_TEST_F(WebNavigationApiTest, Download) {
+  base::ScopedTempDir download_directory;
+  ASSERT_TRUE(download_directory.CreateUniqueTempDir());
+  DownloadPrefs* download_prefs =
+      DownloadPrefs::FromBrowserContext(browser()->profile());
+  download_prefs->SetDownloadPath(download_directory.path());
+
   DownloadTestObserverNotInProgress download_observer(
       content::BrowserContext::GetDownloadManager(profile()), 1);
   download_observer.StartObserving();

chrome/browser/policy/policy_browsertest.cc

@@ -1692,6 +1692,12 @@ IN_PROC_BROWSER_TEST_F(PolicyTest, MAYBE_ExtensionInstallSources) {
   const GURL referrer_url(URLRequestMockHTTPJob::GetMockUrl(
       base::FilePath(FILE_PATH_LITERAL("policy/*"))));
 
+  base::ScopedTempDir download_directory;
+  ASSERT_TRUE(download_directory.CreateUniqueTempDir());
+  DownloadPrefs* download_prefs =
+      DownloadPrefs::FromBrowserContext(browser()->profile());
+  download_prefs->SetDownloadPath(download_directory.path());
+
   const GURL download_page_url(URLRequestMockHTTPJob::GetMockUrl(base::FilePath(
       FILE_PATH_LITERAL("policy/extension_install_sources_test.html"))));
   ui_test_utils::NavigateToURL(browser(), download_page_url);

chrome/browser/prefs/pref_functional_browsertest.cc

@@ -44,26 +44,15 @@ class PrefsFunctionalTest : public InProcessBrowserTest {
 
 IN_PROC_BROWSER_TEST_F(PrefsFunctionalTest, TestDownloadDirPref) {
   ASSERT_TRUE(test_server()->Start());
+  base::ScopedTempDir new_download_dir;
+  ASSERT_TRUE(new_download_dir.CreateUniqueTempDir());
 
-  DownloadManager* download_manager =
-      BrowserContext::GetDownloadManager(browser()->profile());
-  base::FilePath download_dir =
-      (DownloadPrefs::FromDownloadManager(download_manager))->DownloadPath();
-  base::FilePath new_download_dir = download_dir.AppendASCII("my_downloads");
   base::FilePath downloaded_pkg =
-      new_download_dir.AppendASCII("a_zip_file.zip");
+      new_download_dir.path().AppendASCII("a_zip_file.zip");
 
-  // If the directory exists, delete it.
-  if (base::PathExists(new_download_dir)) {
-    base::DeleteFile(new_download_dir, true);
-  }
-
-  // Create the new downloads directory.
-  base::CreateDirectory(new_download_dir);
   // Set pref to download in new_download_dir.
   browser()->profile()->GetPrefs()->SetFilePath(
-      prefs::kDownloadDefaultDirectory,
-      new_download_dir);
+      prefs::kDownloadDefaultDirectory, new_download_dir.path());
 
   // Create a downloads observer.
   scoped_ptr<content::DownloadTestObserver> downloads_observer(