download: Fix Ubuntu crash

In https://crrev.com/710460 I deprecated the use of
base::ProtectedMemory in download_status_updater_linux.cc but forgot to
apply NO_SANITIZE("cfi-icall") to one function, introducing a crash on
download for Ubuntu clients. Fix that crash by marking
EnsureLibUnityLoaded with the same attribute.

Bug: 1020468, 1018834
Change-Id: I904372a3df7828787adfdd9041fa739e89ddc787
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1895373
Auto-Submit: Vlad Tsyrklevich <vtsyrklevich@chromium.org>
Commit-Queue: Xing Liu <xingliu@chromium.org>
Reviewed-by: Xing Liu <xingliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711737}

chrome/browser/download/download_status_updater_linux.cc

@@ -53,6 +53,7 @@ unity_launcher_entry_set_progress_func entry_set_progress = nullptr;
 unity_launcher_entry_set_progress_visible_func entry_set_progress_visible =
     nullptr;
 
+NO_SANITIZE("cfi-icall")
 void EnsureLibUnityLoaded() {
   using base::nix::GetDesktopEnvironment;