Convert //chrome/browser/chromeos from scoped_ptr to std::unique_ptr

chrome/browser/chromeos/drive/download_handler.h

Index: chrome/browser/chromeos/drive/download_handler.h
diff --git a/chrome/browser/chromeos/drive/download_handler.h b/chrome/browser/chromeos/drive/download_handler.h
index d3487eb5cf472ca0e4611feb01e2240c33a14ecb..b732e6a4e3f30ba5a88647804250b7bc1a7f09a1 100644
--- a/chrome/browser/chromeos/drive/download_handler.h
+++ b/chrome/browser/chromeos/drive/download_handler.h
@@ -124,8 +124,8 @@ class DownloadHandler : public AllDownloadItemNotifier::Observer {
   FileSystemInterface* file_system_;  // Owned by DriveIntegrationService.
 
   // Observe the DownloadManager for new downloads.
-  scoped_ptr<AllDownloadItemNotifier> notifier_;
-  scoped_ptr<AllDownloadItemNotifier> notifier_incognito_;
+  std::unique_ptr<AllDownloadItemNotifier> notifier_;
+  std::unique_ptr<AllDownloadItemNotifier> notifier_incognito_;
 
   // Temporary download location directory.
   base::FilePath drive_tmp_download_path_;