Add log for extension garbage collection finished on file thread

Chrome app crash recovery flow requires the primary app to be installed.
But, if the chrome app crashes before the extensions garbage collection
has ended, the primary app extension is not found at the time of crash
recovery. This log is required in Tast test to make sure that the
extensions garbage collection is finished before the crash is initiated.

This is a temporary solution and the log will be removed once we find a
solution to remove this dependency of primary kiosk app extension is not
getting cached.

Bug: 379867155
Change-Id: I565e85d7169c9adcc4db800d30fd6777703161a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6049856
Reviewed-by: David Bertoni <dbertoni@chromium.org>
Commit-Queue: Ashutosh Singhal <macinashutosh@google.com>
Cr-Commit-Position: refs/heads/main@{#1388205}
diff --git a/chrome/browser/extensions/extension_garbage_collector.cc b/chrome/browser/extensions/extension_garbage_collector.cc
index 943113d9..9b7565e 100644
--- a/chrome/browser/extensions/extension_garbage_collector.cc
+++ b/chrome/browser/extensions/extension_garbage_collector.cc
@@ -18,6 +18,7 @@
 #include "base/one_shot_event.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/syslog_logging.h"
 #include "base/task/sequenced_task_runner.h"
 #include "base/task/single_thread_task_runner.h"
 #include "base/time/time.h"
@@ -178,6 +179,10 @@
     unpacked ? CheckUnpackedExtensionDirectory(extension_path, extension_paths)
              : CheckExtensionDirectory(extension_path, extension_paths);
   }
+  // TODO(crbug.com/379867155) Remove this after chrome app kiosk crash recovery
+  // is independent of extensions garbage collection.
+  SYSLOG(INFO)
+      << "Garbage collection for extensions on file thread is complete.";
 }
 
 void ExtensionGarbageCollector::GarbageCollectExtensions() {