Fix timeout in ChromeDownloadManagerDelegateTest.LastSavePath.

See https://crbug.com/879348 for a description of the issue. This CL
adds a DownloadPrefs::ReinitializeDefaultDownloadDirectoryForTesting()
method to force the global DefaultDownloadDirectory instance to
reinitialize itself to take into account any test configurations.

Bug: 879348
Change-Id: I4a2340fad5f1396196e6746073857d3a09bfa7c1
Reviewed-on: https://chromium-review.googlesource.com/1197724Reviewed-by: Min Qin <qinmin@chromium.org>
Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589291}

chrome/browser/download/chrome_download_manager_delegate_unittest.cc

@@ -7,7 +7,6 @@
 
 #include <string>
 
-#include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
@@ -257,8 +256,6 @@ class ChromeDownloadManagerDelegateTest
   void GetNextId(uint32_t next_id) { download_ids_.emplace_back(next_id); }
 
  private:
-  // Resets the global cached DefaultDownloadDirectory instance.
-  base::ShadowingAtExitManager at_exit_manager_;
   base::ScopedPathOverride download_dir_override_{
       chrome::DIR_DEFAULT_DOWNLOADS};
   sync_preferences::TestingPrefServiceSyncable* pref_service_;
@@ -273,6 +270,7 @@ ChromeDownloadManagerDelegateTest::ChromeDownloadManagerDelegateTest()
 }
 
 void ChromeDownloadManagerDelegateTest::SetUp() {
+  DownloadPrefs::ReinitializeDefaultDownloadDirectoryForTesting();
   ChromeRenderViewHostTestHarness::SetUp();
 
   CHECK(profile());

chrome/browser/download/download_prefs.cc

@@ -13,9 +13,9 @@
 #include "base/bind_helpers.h"
 #include "base/feature_list.h"
 #include "base/files/file_util.h"
-#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/no_destructor.h"
 #include "base/path_service.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
@@ -86,10 +86,7 @@ class DefaultDownloadDirectory {
  public:
   const base::FilePath& path() const { return path_; }
 
- private:
-  friend struct base::LazyInstanceTraitsBase<DefaultDownloadDirectory>;
-
-  DefaultDownloadDirectory() {
+  void Initialize() {
     if (!base::PathService::Get(chrome::DIR_DEFAULT_DOWNLOADS, &path_)) {
       NOTREACHED();
     }
@@ -102,13 +99,20 @@ class DefaultDownloadDirectory {
     }
   }
 
+ private:
+  friend class base::NoDestructor<DefaultDownloadDirectory>;
+
+  DefaultDownloadDirectory() { Initialize(); }
+
   base::FilePath path_;
 
   DISALLOW_COPY_AND_ASSIGN(DefaultDownloadDirectory);
 };
 
-base::LazyInstance<DefaultDownloadDirectory>::DestructorAtExit
-    g_default_download_directory = LAZY_INSTANCE_INITIALIZER;
+DefaultDownloadDirectory& GetDefaultDownloadDirectorySingleton() {
+  static base::NoDestructor<DefaultDownloadDirectory> instance;
+  return *instance;
+}
 
 }  // namespace
 
@@ -262,9 +266,14 @@ base::FilePath DownloadPrefs::GetDefaultDownloadDirectoryForProfile() const {
 #endif
 }
 
+// static
+void DownloadPrefs::ReinitializeDefaultDownloadDirectoryForTesting() {
+  GetDefaultDownloadDirectorySingleton().Initialize();
+}
+
 // static
 const base::FilePath& DownloadPrefs::GetDefaultDownloadDirectory() {
-  return g_default_download_directory.Get().path();
+  return GetDefaultDownloadDirectorySingleton().path();
 }
 
 // static

chrome/browser/download/download_prefs.h

@@ -43,6 +43,8 @@ class DownloadPrefs {
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
+  static void ReinitializeDefaultDownloadDirectoryForTesting();
+
   // Returns the default download directory.
   static const base::FilePath& GetDefaultDownloadDirectory();