Change linux default hidden file save directory to XDG_DATA_HOME

chrome/browser/download/chrome_download_manager_delegate.cc

Index: chrome/browser/download/chrome_download_manager_delegate.cc
diff --git a/chrome/browser/download/chrome_download_manager_delegate.cc b/chrome/browser/download/chrome_download_manager_delegate.cc
index 67ea6dc5e69d015ad762896bce3ae4ce31c905ec..3c92692ad7aaed1921b1bf96e9962cb36ac1faa0 100644
--- a/chrome/browser/download/chrome_download_manager_delegate.cc
+++ b/chrome/browser/download/chrome_download_manager_delegate.cc
@@ -448,6 +448,19 @@ void ChromeDownloadManagerDelegate::GetSaveDir(
   *website_save_dir = download_prefs_->SaveFilePath();
   DCHECK(!website_save_dir->empty());
   *download_save_dir = download_prefs_->DownloadPath();
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+  // TODO(thomasanderson): Remove this when all Linux distros with
+  // versions of GTK lower than 3.14.7 are no longer supported.  This
+  // should happen when support for Ubuntu Trusty and Debian Jessie
+  // are removed.
+  //
+  // Use /var/tmp instead of /tmp here because /tmp may be
+  // memory-mounted and users may want to download files larger than
+  // will fit in memory.  Existence of /var/tmp is guaranteed by the
+  // Filesystem Hierarchy Standard.
+  static const char kVarTmp[] = "/var/tmp";
+  *download_save_dir = base::FilePath(kVarTmp);

[qinmin, 2017/06/06 22:10:14]

Shouldn't this be done in download_prefs_?
what if the *download_save_dir is defaulted to something else, either by test or
by user 

[Tom Anderson, 2017/06/07 01:29:51]

Done.

+#endif
   *skip_dir_check = false;
 #if defined(OS_CHROMEOS)
   *skip_dir_check = drive::util::IsUnderDriveMountPoint(*website_save_dir);