Make use of unique_ptr more modern

- No change to behavior

BUG=None
TEST=compiles

Change-Id: I55d53415dbce1b004fdda015695d3a10b7eb118c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1607121Reviewed-by: Sean Kau <skau@chromium.org>
Commit-Queue: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#658847}

chrome/browser/chromeos/printing/cups_print_job_manager.cc

@@ -12,8 +12,8 @@
 namespace chromeos {
 
 CupsPrintJobManager::CupsPrintJobManager(Profile* profile) : profile_(profile) {
-  notification_manager_.reset(
-      new CupsPrintJobNotificationManager(profile, this));
+  notification_manager_ =
+      std::make_unique<CupsPrintJobNotificationManager>(profile, this);
 }
 
 CupsPrintJobManager::~CupsPrintJobManager() {